Grignard Reagent

1598 Organometallics 2009, 28, 1598–1605 CoVer Essay The Grignard Reagents Dietmar Seyferth Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 ReceiVed February 4, 2009 During the past 100 years the Grignard reagents probably have been the most widely used organometallic reagents. Most of them are easily prepared in ethereal solution (usually diethyl ether or, since the early 1950s, THF) by the reaction of an organic halide with metallic magnesium (eq 1).Table 1. Composition of Diethyl Ether Solutions of Various Grignard Reagents at Equilibrium (in mol %), 2RMgX h R2Mg + MgX2a RX in RX + Mg reacn CH3I C2H5I C2H5Br C2H5Cl n-C3H7I n-C3H7Br n-C3H7Cl C6H5I C6H5Br a RMgX 87. 0 43. 0 41. 0 15. 0 24. 0 24. 0 17. 0 38. 0 30. 0 R2Mg ) MgX2 6. 5 28. 5 29. 5 42. 5 38. 0 38. 0 41. 5 31. 0 35. 0 RX + Mg f RMgX (X ) Cl, Br, I) (1) Most of them are stable in ethereal solution (although atmospheric moisture and oxygen should be excluded) and in gene ral are quite reactive.Discovered by Victor Grignard at the University of Lyon in France in 1900,1 their ease of preparation and their broad applications in organic and organometallic synthesis made these new organomagnesium reagents an instant success. The importance of this contribution to synthetic chemistry was recognized very early, and for his discovery Grignard was awarded a Nobel Prize in Chemistry in 1912. Our cover molecule is the monomeric ethylmagnesium bromide bis(diethyl etherate) (1), whose solid-state molecular structure was determined by an X-ray diffraction study by Lloyd Guggenberger and RobertRundle in 1964 using crystals isolated from a diethyl ether solution of a C2H5Br/Mg reaction mixture by slow cooling with a stream of cold gaseous nitrogen. 2-4 Adapted from: Schlenk, W. , Jr. Ber. Dtsch. Chem. Ges. 1931, 64, 734. Wilhelm Schlenk and his son discovered 80 years ago, more than one magnesium-containing species exists in the diethyl ether solution of a Grignard reagent. 5 A redistribution of the substituents on magnesium takes place, and the RMgX species ends up in equilibrium with the two symmetrical species, the diorganomagnesium and the magnesium dihalide: the â€Å"Schlenk Equilibrium† (eq 2). 2RMgX h R2Mg + MgX2 (2) Generally written as â€Å"RMgX† in textbooks, monographs and research papers, the Grignard reagents in ethereal solution are more complicated than this simple formula indicates. As (1) (a) Grignard, V. Compt. rend. Hebd. Seances Acad. Sci. 1900, 130, ? 1322. (b) Grignard, V. Dissertation â€Å"Theses sur les combinaisons organo` magnesienes mixtes et leur application a des syntheses†, University of Lyon, ` ` Lyon, France, 1901. (2) (a) Guggenberger, L. J. ; Rundle, R. E. J. Am. Chem. Soc. 1964, 86, 5344. (b) Guggenberger, L. J. ; Rundle, R. E. J. Am. Chem. Soc. 1968, 90, 5375. 3) A crystalline solid, CH3MgI  · (n-C5H11)2O, was isolated and identi? ed as such by elemental analysis (Mg and I) in 1908 : Zerewitinoff, Th. Ber. Dtsch. Chem. Ges. 1908, 41, 2244. The oxonium structure The species that contain Mg-halogen bonds can be precipitated from Grignard reagent solutions in diethyl ether by the addition of 1,4-dioxane. An insoluble, polymeric 1,4-dioxane adduct is formed, leaving behind a solution of R2Mg5sa useful preparation of dialkyl- and diarylmagnesium reagents. 6 Wilhelm Schlenk, Jr. analyzed the 1,4-dioxane precipitations from a number of Grignard reagent solutions. Assuming that the precipitation is essentially instantaneous, i. e. , that the calculated R2Mg, MgX2, and RMgX percentages re? ect the actual composition of the Grignard reagent solution at equilibrium, Schlenk reported the compositions collected in Table 1. Direct evidence (5) Schlenk, W. ; Schlenk, W. , Jr. Ber. Dtsch. Chem. Ges. 1929, 62, 920. (6) (a) Cope, A. C. J. Am. Chem. Soc. 1935, 57, 2238. (b) As Erwin Weiss found, evaporation of diethyl ether solutions of methyl- and ethylmagnesium bromide and chl oride at reduced pressure followed by heating of the colorless solid residues at ca. 00  °C and 0. 001 mmHg for several hours gave a mixture of the respective pure, solvent-free, polymeric R2Mg compounds and magnesium halides. The solid MgCl2 thus obtained differed from a sample obtained from a MgCl2 melt in that its lattice showed a strong stacking disorder. This form of MgCl2 had an extremely high surface area: Weiss, E. Chem. Ber. 1965, 98, 2805. (7) Schlenk, W. , Jr. Ber. Dtsch. Chem. Ges. 1931, 64, 734 Further additions to the examples in Table 1 were soon thereafter reported by other workers: (a) Noller, C. R. ; Hilmer, F. B. J. Am. Chem. Soc. 1932, 54, 2503. (b) Johnson, G. O. Adkins, H. J. Am. Chem. Soc. 1932, 54, 1943. (c) Cope, A. C. J. Am. Chem. Soc. 1934, 56, 1578. was written for this compound. Earlier workers had isolated noncrystalline solid samples of etherates, e. g. , C2H5MgI  · (C2H5)2O and RMgI  · 2(C2H5)2O. (4) Other early Grignard reagent crystal structur es: (a) Stucky, G. D. ; Rundle, R. E. J. Am. Chem. Soc. 1964, 86, 4825 (C6H5MgBr  · 2Et2O). (b) Vallino, M. J. Organomet. Chem. 1969, 20, 1 (CH3MgBr  · 3THF). . 10. 1021/om900088z CCC: $40. 75 ? 2009 American Chemical Society Publication on Web 03/16/2009 Organometallics, Vol. 28, No. 6, 2009 1599 Figure 1.Association of several Grignard compounds in tetrahydrofuran (J. Am. Chem. Soc. 1969, 91, 3847. ). that solutions of â€Å"CH3MgBr† in diethyl ether contain CH3MgBr and (CH3)2Mg was obtained by Ashby and co-workers by means of 1H NMR spectroscopic measurements at -105  °C. Solutions of â€Å"t-butylmagnesium chloride† in diethyl ether also were studied. 8 The tendency of the halide substituents in the RMgX and MgX2 species present in ethereal solution at equilibrium to form bridges between magnesium atoms, Mg-X-Mg, in a Lewis base/Lewis acid type interaction further complicates the nature of the Grignard reagent in ethereal solvents.In a very thorough study of the association factors of various Grignard reagents in diethyl ether and THF by careful ebullioscopic molecular weight measurements, Eugene Ashby and Frank Walker at the Georgia Institute of Technology found that monomeric, dimeric, and higher oligomeric species were present, depending on the solvent and the halogen and the organic substituents on the magnesium atom. 9 Included in this study along with data for the â€Å"RMgX† solutions were data for a few R2Mg compounds and for the magnesium dihalides.As Figure 1 shows, the observed association factor (the i value is the apparent molecular weight divided by the formula weight of the monoetherate) shows that the Grignard reagents and (C6H5)2Mg are close to monomeric in the relatively strong Lewis basic THF. The picture is quite different in diethyl ether solution (Figures 2 and 3), with association factors of 1 to nearly 4 for solute concentrations up to ca. 3 molal. It is not clear what these i values mean in terms of the a ctual species present in these solutions.On the assumption that the Schlenk equilibrium is operative in all cases, in view of the presence of a signi? cant concentration of MgX2, one cannot expect only simple solvated species of type i(R)Mg-X] n [ i (average n ) i). Toney and Stucky isolated crystals of a dimeric species, 2, from a solution of â€Å"C2H5MgBr† in di-n-butyl ether by addition of this solution to triethylamine. 10 The molecular Figure 2. Association of alkylmagnesium chlorides in diethyl ether. Demonstration of importance of halogen vs R group in determining the form of association in diethyl ether (J. Am. Chem. Soc. 1969, 91, 3848. ).Figure 3. Association of several alkyl- and arylmagnesium bromides and iodides and related magnesium compounds in diethyl ether (J. Am. Chem. Soc. 1969, 91, 3848. ). structure, as determined by X-ray analysis, contained a double Br bridge with the ethyl groups in a trans arrangement. That (8) In â€Å"CH3MgBr† solutions in d iethyl ether: (a) Ashby, E. C. ; Parrish, G. ; Walker, F. Chem. Commun. 1969, 1464. (b) â€Å"(CH3)3CMgCl† solutions in diethyl ether at-26  °C: Parris, G. ; Ashby, E. C. J. Am. Chem. Soc. 1971, 93, 1206. (9) (a) Walker, F. W. ; Ashby, E. C. J. Am. Chem. Soc. 1969, 91, 3845. (b) Ashby, E. C. Bull. Soc.Chim. Fr. 1972, 2133 (review, in English). (c) Meisenheimer, J. ; Schlichenmaier. Ber. Dtsch. Chem. Ges. 1928, 61 (an earlier, similar, but more limited study in diethyl ether). more complicated structures can be present in an â€Å"RMgX† solution in diethyl ether was demonstrated by the determination of the X-ray crystal structure of a crystalline compound obtained from a THF solution of â€Å"C2H5MgCl† of composition C2H5Mg2Cl3. This compound was not a simple Cl-bridged dimer, as the empirical formula might suggest. Actually, it was a tetramer (Figure 4) in which the Mg atoms have a coordination number greater than 4. 1 There is a caveat, however: the species t hat crystallizes from a Grignard reagent solution does not necessarily directly re? ect what species are swimming around in the solution. The crystalline solid shown in Figure 4 could well have self-assembled during the crystallization process by combination of two molecules of the C2H5Mg2Cl3 dimer and not been present in solution at all. Even in the case of monomeric â€Å"RMgX† in THF solution, the Schlenk equilibrium will be operative and the strongly Lewis basic THF apparently prevents halide bridging between Mg atoms.Consequently, the (10) Toney, J. ; Stucky, G. D. Chem. Commun. 1967, 1168. (11) Toney, J. ; Stucky, G. D. J. Organomet. Chem. 1971, 28, 5. 1600 Organometallics, Vol. 28, No. 6, 2009 Scheme 1 Figure 4. Molecular structure of [C2H5Mg2Cl3(C4H8O)3]2, a tetrameric Grignard reagent. Modi? ed from Toney and Stucky (J. Organomet. Chem. 1971, 28, 15. (copyright 1971, with permission from Elsevier)). presence of monomeric RMgX, R2Mg, and MgX2, all solvated, would resu lt in the measurement of an association factor of 1, as Walker and Ashby observed.There are so many factors that bear on the question of the constitution of a given Grignard reagent in ethereal solutionsthe Lewis basicity and steric properties of the ether solvent, the electronegativity and size of the halogen atom in RMgX, the nature and steric properties of the organic substituent on the magnesium atom. These will affect the magnitude of the equilibrium constant of the Schlenk equilibrium and the extent of Mg-X-Mg bridging. For most applications in synthetic chemistry it will suf? ce to take the easy way outsto regard and to write the Grignard reagent as RMgX.There is another interesting and useful property of ethereal Grignard reagent solutions. The magnesium species are weak electrolytes in such solvents of low dielectric constant, and â€Å"RMgX† solutions conduct an electric current. 12 The electrolysis of solutions of organomagnesium halides was studied in some detail by Kondyrew at the State Research Institute in Leningrad13 and by Ward Evans and his students at Northwestern University. 14 During the electrolysis, magnesium species migrate both to the cathode and to the anode. Scheme 1 shows the simplest picture based on RMgX. Metallic magnesium is formed at the cathode. 12) The earliest report appears to be a 1912 French paper: Jolibois, P. Compt. rend. Hebd. Seances Acad. Sci. 1912, 155, 213. See also: Nelson, ? J. M. ; Evans, W. V. J. Am. Chem. Soc. 1917, 39, 82. (13) (a) Kondyrew, N. W. Ber. Dtsch. Chem. Ges. 1925, 58, 459. (b) Kondyrew, N. W. ; Manojew, D. P. Ber. Dtsch. Chem. Ges. 1925, 58, 464. (c) Kondyrew, N. W. Ber. Dtsch. Chem. Ges. 1928, 61, 208. (d) Kondyrew, N. W. ; Ssusi, A. K. Ber. Dtsch. Chem. Ges. 1929, 62, 1856. (14) The Evans group published many papers in J. Am. Chem. Soc. during the 1933-1942 period. See, for example: (a) Evans, W. V. ; Lee, F.H. J. Am. Chem. Soc. 1934, 56, 654. (b) Evans, W. V. ; Field, E. J. Am. Chem. Soc . 1936, 58, 720. (c) Evans, W. V. ; Braithwaite, D. J. Am. Chem. Soc. 1939, 61, 898. (d) Evans, W. V. ; Braithwaite, D. ; Field, E. J. Am. Chem. Soc. 1940, 62, 534. (e) Evans, W. V. ; Pearson, R. J. Am. Chem. Soc. 1942, 64, 2865. The alkyl radicals formed at the anode can undergo the usual alkyl radical processes of coupling (to R-R), disproportionation (to RH + R(-H)), or, if the anode is composed of a reactive metal such as zinc, aluminum, cadmium, or lead, they can attack the anode to form an organometallic compound.A graduate student of Evans, David G. Braithwaite, joined the Nalco Chemical Co. after he graduated and developed an electrolytic process for the commercialscale syntheses of tetramethyl- and tetraethyllead antiknock agents in which the respective alkyl Grignard reagents were electrolyzed in a mixed THF/diethylene glycol dimethyl ether solvent system using a lead anode and a steel cathode. 15 The reactions of the Grignard reagents with organic, organometallic, and ino rganic substrates and their applications are too numerous and varied to be covered here.Not only do they ? nd extensive use on a small to moderate scale in research laboratories but they also have been prepared and utilized on a large scale in diverse industrial processes. For the most part they react as nucleophilic reagents, as would be expected, on the basis of the polarity of the carbon-magnesium bond, C? –Mg? +. However, they also can undergo electron transfer reactions with appropriate electron-acceptor substrates. They are weak bases capable of deprotonating the stronger weak organic acids such as terminal acetylenes and cyclopentadiene.Their basicity can be enhanced (as can be the basicity of organolithium reagents) by the addition to RMgX solutions in ethers of additives such as hexamethylphosphoric triamide (HMPA) and N-methyl-2-pyrrolidinone (NMP) or alkali-metal alkoxides. All such information can be found in books devoted solely or in part to Grignard reagents. 1 6 Two special topics are of current interest and merit special mention. (1) The preparation of highly functionalized organomagnesium reagents by Paul Knochel and his co-workers at the University of Munich17 by means of halogen-magnesium exchange (e. . , eq 3). The availability of reagents such as 3-8 (which must be utilized at low temperature) has added a new and spectacular dimension to Grignard reagent chemistry. (2) The synthesis of ole? ns, styrenes, 1,3-dienes and biaryl derivatives by the crosscoupling of Grignard reagents with organic halides. The crosscoupling of Grignard reagents with vinylic halides was discovered by Morris Kharasch and Charles Fuchs at the University of Chicago Organometallics, Vol. 28, No. 6, 2009 1601 Table 2.Transition Metal Halide Catalyzed Homocoupling of Phenylmagnesium Iodidea metal halide FeCl2 CoBr2 NiBr2 RuCl3 RhCl3 PdCl2 OsCl3 IrCl3 a amt, mol 0. 01 0. 01 0. 03 0. 0036 0. 0036 0. 00566 0. 00275 0. 003 amt of C6H5MgI, mol 0. 03 0. 03 0. 095 0. 0 108 0. 013 0. 0163 0. 007 0. 01 yield of biphenyl, % 98 98 100 99 97. 5 98 53 28 Taken from: J. Am. Chem. Soc. 1939, 61, 957. in 1943 during the classic studies of Kharasch on the chemistry of Grignard reagents in the presence of transition-metal halides. 6b Kharasch and Fuchs found that arylmagnesium bromides in diethyl ether reacted readily with vinylic halides of type RCHdCHX and R2CdCHX (but not CH2dC(R)X) to give styrenes in 50-75% yield when the reactions were carried out in the presence of 5 mol % of CoCl2 (eq 4). 18It was reported that other metal halides (of iron, nickel, and chromium) also were effective catalysts of this cross-coupling reaction. Benzylmagnesium chloride also reacted in this manner with vinyl bromide to give PhCH2CHdCH2 in 75% yield.Alkylmagnesium halides such as cyclohexyl- and n-butylmagnesium bromide, on the other hand, gave only â€Å"small to negligible† yields of the expected coupling product. The ArMgBrderived biaryl usually was obtained as a byproduct in these reactions. Such homocoupling of arylmagnesium halides in the presence of a transition metal halide as well as copper and silver halides was a known reaction. It had been investigated in 1939 by Gilman and Lichtenwalter, who found that aryl Grignard reagents undergo homocoupling in the presence of ca. 0 mol % of various transition-metal halides in diethyl ether solution to give the respective biaryl in high yield in most cases (eq 5, Table 2). 19 The metal halide, in addition to being the needed catalyst precursor, also served as an oxidizing agent and, in some cases (CoBr2, NiCl2, RhCl3), formation of a black solid indicated complete reduction to the metal. not occur in the absence of the organic halide but in its presence was vigorously exothermic. The added organic halide was only partially consumed and did not show up in the biaryl product.When p-bromotoluene was added to a phenylmagnesium bromide/CoCl2 catalyst reaction mixture, only biphenyl was formed. A re markable reaction! smost likely a free radical process, as Kharasch suggested. The organic halide was believed to function as an oxidizing agent. This interesting, simple, and potentially useful cross-coupling reaction, as exempli? ed in eq 4, was not adopted by the synthetic organic community right away. After a long dormancy it was rediscovered some 30 years later by a number of groups in the USA, Japan, and France, all of whom apparently were not aware of the 1943 Kharasch/Fuchs JACS paper. 1 Transition-metal catalysts other than CoCl2 were used, but the concept and the basic reaction were the same. In 1971 Tamura and Kochi reported a thorough study of the cross-coupling of Grignard reagents with vinylic halides catalyzed by soluble iron species in concentrations of ca. 10-4 M in THF at 0-25  °C. 26,27 Various Fe(III) compounds could be used as Fe catalyst precursors; the best were Fe(III) -diketonates such as Fe(RC(O)CHC(O)R)3 (R ) Ph, CH3, t-Bu). These exothermic reactions we re not free radical processes. The reactions of cis- and trans-propenyl bromide proceeded with retention of geometric con? uration (eqs 6 and 7) and were not adversely affected by the presence of 0. 4 M styrene. A ArMgBr + RCHdCHX 9 ArCHdCHR + MgBrX 8 (X ) Cl, Br) CoCl2 5 mol % (4) 2ArMgX + MXn f Ar-Ar + MgX2 + MXn-2 (5) A novel catalytic process for such ArMgX to Ar-Ar coupling was discovered by Kharasch and Fields when ethereal solutions of an aryl Grignard reagent that contained a catalytic amount (3 mol %) of CoCl2 were heated at re? ux for 1 h and then treated with an equivalent amount of an organic halide (C6H5Br, C2H5Br, i-C3H7Cl). 20 The coupling reaction to give Ar-Ar did (15) (a) Bott, L.L. Hydrocarbon Process. Petrol. Re? ner 1965, 44, 115. (b) Guccione, E. Chem. Eng. 1965, (June 21), 102. See also Part 2 of the tetraethyllead essay: (c) Seyferth, D. Organometallics 2003, 22, 5154 (pages 5172-5174). (16) (a) Krause, E. ; von Grosse, A. Die Chemie der metall-organischen Ve rbindungen; Gebruder Borntrager: Berlin, 1937; pp 14-61, 110-114. ? ? (b) Kharasch, M. S. ; Reinmuth, O. Grignard Reactions of Nonmetallic Substances; Prentice Hall: New York, 1954. (c) Handbook of Grignard Reagents; Silverman, G. S. , Rakita, P. E. , Eds. ; Dekker: New York, 1996. d) Grignard Reagents-New DeVelopments; Richey, H. G. , Ed. ; Wiley: Chichester, New York, 2000. (e) The Chemistry of Organomagnesium Compounds; Rappaport, Z. , Marek, L. , Eds. ; Wiley-VCH: Weinheim, Germany, 2008. (17) Knochel, P. ; Dohle, W. ; Gommermann, N. ; Kneisel, F. F. ; Kopp, F. ; Korn, T. ; Sapountzis, J. ; Vu, V. A. Angew. Chem. , Int. Ed. 2003, 42, 4302 (review). (18) Kharasch, M. S. ; Fuchs, C. F. J. Am. Chem. Soc. 1943, 65, 504. (19) Gilman, H. ; Lichtenwalter, M. J. Am. Chem. Soc. 1939, 61, 957. and earlier (back to 1914) references cited therein. 20) Kharasch, M. S. ; Fields, E. K. J. Am. Chem. Soc. 1941, 63, 2316. mechanism involving an organoiron(I) intermediate, obtained by reduction of the Fe(III) precursor by the Grignard reagent, was suggested. The results of a few experiments carried out on a 30-40 mmol scale (Table 3) showed that such iron-catalyzed reactions would be useful in the synthesis of ole? ns, but a broader study to optimize them and to broaden the scope of their application was not undertaken. The coupling of vinylic Grignard reagents with alkyl halides is catalyzed also by Ag(I) salts. 8 Thus, cis-propenylmagnesium (21) Two later â€Å"historical notes†22,23 and two book chapters24,25 that dealt with the cross-coupling reactions of Grignard reagents with vinylic halides also did not cite the Kharasch/Fuchs paper. (22) Tamao, K. J. Organomet. Chem. 2002, 653, 27. (23) Murahashi, S. -I. J. Organomet. Chem. 2002, 653, 27. (24) Kochi, J. K. Organometallic Mechanisms and Catalysis; Academic Press: New York, 1978; Chapter 14, Sections III and IV. (25) Hou, S. ; Negishi, E. -i. In Handbook of Organopalladium Chemistry; Negishi, E. -i. , Ed. , Wile y: New York, 2002; Vol. 1,Chapter III. 2. 6, pp 335408.As a historical note, the following quotation from this reference (p 335) is of interest: â€Å"Although the reaction of Grignard reagents with organic halides was shown to be catalyzed by various late transition metal compounds (the Kharasch reaction) in the 1950s, it was not until the early 1970s that the applicability of this catalytic method was extended to the cross-coupling involving alkenyl and aryl halides catalyzed by Ag, Fe and other late transition metals. † (26) (a) Kochi, J. ; Tamura, M. J. Am. Chem. Soc. 1971, 93, 1487. (b) Tamura, M. ; Kochi, J. Synthesis, 1971, 303. (27) Full papers: (a) Neumann, S.M. ; Kochi, J. K. J. Org. Chem. 1975, 40, 599. (b) Smith, R. S. ; Kochi, J. K. J. Org. Chem. 1976, 41, 502. (c) Reviews: ref 24. (d) Kochi, J. K. J. Organomet. Chem. 2002, 653, 11 (historical note). (28) (a) Whitesides, G. M. ; Casey, C. P. J. Am. Chem. Soc. 1966, 88, 4541. (b) Tamura, M. ; Kochi, J. J. Am. Chem . Soc. 1971, 93, 1483. 1602 Organometallics, Vol. 28, No. 6, 2009 Table 3. Alkenylation of Grignard Reagents using FeCl3 as Precatalyst (in THF)a R MgBr (amt, mmol) n-C6H13MgBr (40) CH2dCH(CH2)4MgBr (36) n-C6H13MgBr (40) a 1 R2Br (amt, mmol) CH2dCHBr (204) CH2dCHBr (102) CH3CHdCHBr (355)FeCl3 (amt, mmol) 0. 05 0. 05 0. 10 reacn temp,  °C 0 25 25 product (yield, %) n-C6H13CHdCH2 (83) CH2dCH(CH2)4CHdCH2 (64) n-C6H13CHdCHCH3 (67) (53/47 cis/trans mixture) Taken from: Synthesis 1971, 6, 303. Scheme 2 bromide reacted with methyl bromide in THF in the presence of an Ag(I) catalyst to give cis-butene-2, but a similar reaction of trans-propenylmagnesium bromide gave a 7:3 mixture of cisand trans-butene-2, respectively. 28b Apparently propenyl radicals were involved. A similar Grignard reagent based cross-coupling, ole? n synthesis in which a copper(I) catalyst was used was published by French workers. 9 Normant et al. reported that their reactions (e. g. , n-Bu(Et)CdCHI + i-PrMgCl in THF at -20  °C with a Cu(I) catalyst) proceeded with retention of con? guration. 29a For a reaction of CH3CHdC(CH3)MgCl with n-C3H7I in THF at 0  °C using CuI as catalyst, Linstrumelle reported that the coupling product obtained in 97% yield was 88% cis and 12% trans, while a similar reaction of CH2dC(CH3)MgBr with trans-n-C6H13CHdCHI gave a 4:1 trans/cis product. 29b TheuseofNi(II)catalystprecursorsforGrignardreagent-vinylic halide cross-coupling was reported in 1972 by Corriu and Masse30 and by Tamao, Sumitani, and Kumada. 1 The French group found Ni(II) acetylacetonate to be the most effective catalyst precursor, while the Japanese group favored a bis(tertiary phosphine)NiCl2 catalyst precursor and, especially, chelating diphosphine complexes such as (Ph2PCH2CH2PPh2)NiCl2. Reactions carried out in diethyl ether at re? ux generally gave excellent yields. This procedure has been carried out commercially on an industrial scale in the preparation of p-chloroand p-tert-butylstyrene. 3 2 Finally, the last to be discovered at that time and the most versatile procedure for the cross-coupling of Grignard reagents (29) (a) Normant, J. F. Commercon, A. ; Cahiez, G. ; Villieras, J. Compt. ? rend. Hebd. Seances Acad. Sci. , Ser. C 1974, 278, 967. (b) Derguini? Boumechal, F. ; Linstrumelle, G. Tetrahedron Lett. 1976, 3225. (30) Corriu, R. J. P. ; Masse, J. P. J. Chem. Soc. , Chem. Commun. 1972, 144. (31) (a) Tamao, K. ; Sumitani, K. ; Kumada, M. J. Am. Chem. Soc. 1972, 94, 1375. (b) See also ref 22. Later work: (c) Tamao, K. ; Kiso, Y. ; Sumitani, K. ; Kumada, M. J. Am. Chem. Soc. 1972, 94, 9268. (d) Kiso, Y. ; Tamao, K. ; Kumada, M. J. Organomet. Chem. 1973, 50, C12. (e) Kiso, Y. ; Tamao, K. ; Miyake, N. ; Yamamoto, K. ; Kumada, M. Tetrahedron Lett. 974, (No. 1), 3. (f) Tamao, K. ; Sumitani, K. ; Kiso, Y. ; Zembayashi, M. ; Fujioka, A. ; Kodama, S. ; Nakajima, I. ; Minato, A. ; Kumada, M. Bull. Chem. Soc. Jpn. 1976, 49, 1958. (g) Tamao, K. ; Kodama, S. ; Nakajima, I. ; K umada, M. ; Minato, A. ; Suzuki, K. Tetrahedron 1982, 38, 3347. (32) Banno, T. ; Hayakawa; Umeno, M. J. Organomet. Chem. 2002, 653, 288. (33) (a) Yamamura, M. ; Moritani, I. ; Murahashi, S. -I. J. Organomet. Chem. 1975, 91, C39. Full paper: (b) Murahashi, S. -I. ; Yamamura, M. ; Yanagisawa, K. -i. ; Mita, N. ; Kondo, K. J. Org. Chem. 1979, 44, 2408. (c) Historical note: ref 23. ith vinylic and aryl halides, that catalyzed by palladium complexes, was reported by Shun-Ichi Murahashi and coworkers in 1975. 33a The reactions were carried out in diethyl ether/benzene at room temperature using (Ph3P)4Pd as the catalyst precursor, and they proceeded stereospeci? cally in excellent yield (Scheme 2). Dang and Linstrumelle also used this procedure to prepare 1,3-dienes stereospeci? cally by the reaction of vinylic iodides with vinylic Grignard reagents. 34 Palladium-catalyzed cross-coupling of Grignard reagents with organic halides has been a very active area in organic synthesis.Reference 25 reviews (up to 2002) its application in (alkenyl) MgX-ArX, ArMgX-(alkenyl)X, and (alkenyl)MgX-(alkenyl)X coupling processes. A further chapter in this book deals with ArMgX-Ar? X coupling. 35 Another surge of research activity on cross-coupling of Grignard reagents with organic halides started around the turn of the century and still appears to be in progress at the present time (January 2009). Interest has revived in the use of iron complexes as precatalysts for the cross- and homocoupling of Grignard reagents,36 since iron complexes are cheaper than those of palladium and are nontoxic.The iron-catalyzed cross-coupling of organomagnesium bromides with vinylic bromides, although it produced ole? ns in good yield, was of interest to Jay Kochi, as noted above, primarily from the point of view of its reaction mechanism rather than of its potential for application in organic synthesis. After some 25 years several research groups carried out much experimental work which has shown iron-c atalyzed cross-coupling and homocoupling of Grignard reagents to be broadly applicable and very useful additions to the methods of organic synthesis.In 1995 Gerard Cahiez, at the Universite Pierre et Marie Curie ? ? in Paris, during the course of his extensive investigations of organomanganese chemistry, found that the cross-coupling of vinylic bromides with alkyl, vinylic, and phenylmanganese chlorides could be effected in good yield in the presence of 3 mol % of iron(III) acetylacetonate in a THF/N-methyl-2pyrrolidinone (NMP) mixed solvent at room temperature. 37 In a thorough study, this reaction was extended to the crosscoupling of vinylic halides with alkylmagnesium halides using 1 mol % of Fe(acac)3 and the same solvent mixture. 8 High yields of ole? nic products were obtained. Successful crosscoupling of Grignard reagents with AcO(CH2)6CHdCHCl, CH3C(O)(CH2)3CHdCHCl, Cl(CH2)4CBrdCH2, 9, and 10 are noteworthy as examples of the selectivity and functional group tolerance of this reaction. The scope of this chemistry was extended further when some of Knochel’s functionally substituted aryl Grignard reagents17 (vide supra) were reacted with vinylic bromides and iodides. 39 The cross-coupling reaction between aryl Grignard reagents and vinylic bromides and iodides also was found by Cahiez and co-workers to give ole? ic products in good yield with Organometallics, Vol. 28, No. 6, 2009 1603 Table 4. Iron-Catalyzed Biaryl Coupling Reactions a Table 5. Iron-Catalyzed Homocoupling of Grignard Reagents with Atmospheric Oxygen as Oxidanta a Taken from: J. Am. Chem. Soc. 2007, 129, 13788. palladium or nickel precatalysts. 42 Of these procedures, that of Cahiez et al. 41f appears to be the most useful. Alkyl halide/ alkylmagnesium halide cross-coupling is not a practical process. 43 RMgX + R? X 9 R-R? + MgX2 8 [Fe] (8)Iron-catalyzed reactions of aryl Grignard reagents with aryl halides to give biaryls generally are not synthetically useful. The desired cross-co upling products are obtained in only poor yield, the main product being the homocoupled biaryl derived from the aryl Grignard reagent (eq 9) (recall the Gilman/ Lichtenwalter and Kharasch/Fields reactions, vide supra). ArMgX + Ar? X f Ar-Ar? + (low yield) (major Ar-Ar product) (9) a Taken from: J. Am. Chem. Soc. 2007, 129, 9844. retention of geometric con? guration when carried out in THF solution in the presence of 10 mol % of MnCl2. 0 As noted above, Kharasch and Fuchs had found that attempts to cross-couple aryl Grignard reagents with alkyl halides in the presence of catalytic amounts of CoCl2 were unsuccessful. On the other hand, such reactions do occur in the presence of an iron precatalyst and various additives (eq 8, R? ) alkyl), as summarized in ref 36. A number of other groups have reported the results of their research directed toward development of an effective procedure for the process shown in eq 8, all using an iron precatalyst of one kind or another, various additives such as TMEDA, NMP, etc. nd generally diethyl ether (but sometimes THF) as solvent. 41 It is noteworthy that primary and secondary alkyl halides, i. e. , ones that contain hydrogen substituents on the carbon atom, can be cross-coupled with aryl Grignard reagents, a process that cannot be realized using (34) Dang, H. P. ; Linstrumelle, G. Tetrahedron Lett. 1978, 191. (35) Anastasia, L. ; Negishi, E. -i. Chapter II. 2. 5, pp 311-344, in ref 25. (To date palladium and nickel catalysts have been widely used to effect aryl-aryl cross-coupling reactions. However, arylmagnesium halides were found to undergo cross-coupling with aryl halides that contain electron-withdrawing activating substituents ortho or para with respect to the halogen substituent in the presence of 10 mol % of manganese(II) chloride (eq 10). 44 Cyclohexyl and 2-methylpropenyl Grignard reagents reacted with such substituted halobenzenes in a similar manner. Very (36) (a) Cahiez, G. ; Duplais, C. â€Å"Iron-Catalyzed Re actions of Grignard Reagents†, Chapter 13, pp 594-630 in ref 16e. (b) Furstner, A. ; Leitner, ? A. ; Mendez, M. ; Kraus, H. J. Am.Chem. Soc. 2002, 124, 13856 (a long ? paper that brings an excellent discussion of the literature, of questions concerning mechanism, and original results). (c) Sherry, B. D. ; Furstner, ? A. Acc. Chem. Res. 2008, 41, 1500. (37) Cahiez, G. ; Marquis, S. Tetrahedron Lett. 1996, 37, 1773. (38) Cahiez, G. ; Avedissian, H. Synthesis 1998, 1199. (39) Dohle, W. ; Kopp, F. ; Cahiez, G. ; Knochel, P. Synlett 2001, 1901. 1604 Organometallics, Vol. 28, No. 6, 2009 Table 6. Manganese-Catalyzed Homocoupling of Grignard Reagents with Atmospheric Oxygen as Oxidanta Scheme 4THF to a mixture of 3 mol % of FeF3  · 3H2O and 9 mol % of an N-heterocyclic carbene (SIPr  · HCl). In one example, chlorobenzene (1. 0 equiv) and p-CH3C6H4MgBr (1. 2 equiv) were added to this catalyst system and the reaction mixture was stirred at 60  °C for 1 day. The desired product, p -CH3C6H4-C6H5, was obtained in 98% yield. The homocoupling product, biphenyl, was present only in trace amount, while CH3C6H4C6H4CH3 was formed in 3% yield. Some examples of the application of this remarkable reaction are shown in Table 4. Good results were obtained only with aryl chlorides.Aryl bromides and iodides gave low biaryl yields. A German group reported similar MnCl2-catalyzed cross-coupling between various heterocyclic chlorides and aryl as well as alkyl Grignard reagents: e. g. , eq 11. 46 a Taken from: J. Am. Chem. Soc. 2007, 129, 13788. The homocoupling reaction of aryl Grignard reagents, mentioned earlier, also has received renewed attention recently, and synthetically useful procedures have resulted. Nagano and Hayashi developed a procedure in which the reaction is carried out in re? uxing diethyl ether in the presence of 1-5 mol % of FeCl3, NMP and 1. molar equiv of 1,2-dichloroethane (which serves as the oxidant). 47 Cahiez and co-workers have improved this procedu re by using THF as solvent, in which arylmagnesium halides, including the chlorides, are more easily prepared. 48 This procedure works well with Knochel’s functional arylmagnesium halides (Scheme 3). Of interest also is the clever construction of the tricyclic system 11 by intramolecular homocoupling (Scheme 4). (40) (a) Cahiez, G. ; Gager, O. ; Lecomte, F. Org. Lett. 2008, 10, 5255. (b) Alami, M. ; Ramiandrasoa, P. ; Cahiez, G. Synlett 1998, 325. 41) A selection: (a) Martin, R. ; Furstner, A. Angew. Chem. , Int. Ed. ? 2004, 43, 3955 (see also ref 36b and references cited therein). (b) Nagano, T. ; Hayashi, T. Org. Lett. 2004, 6, 1297. (c) Bedford, R. B. ; Bruce, D. W. ; Frost, R. M. ; Goodby, J. W. ; Hird, M. Chem. Commun. 2004, 2822. (d) Nakamura, N. ; Matsuo, K. ; Ito, S. ; Nakamura, E. J. Am. Chem. Soc. 2004, 126, 3686. (e) Bedford, R. B. ; Bruce, D. W. ; Frost, R. M. ; Hird, M. Chem. Commun. 2005, 4161. (f) Cahiez, G. ; Habiak, V. ; Duplais, C. ; Moyeux, A. Angew. Chem. , Int. Ed. 2007, 46, 4364. g) Cahiez, G. ; Duplais, C. ; Moyeux, A. Org. Lett. 2007, 9, 3253. (h) Guerinot, A. ; Reymond, S. ; Cossy, J. Angew. ? Chem. , Int. Ed. 2007, 46, 6521. (42) However, Terao and Kambe have recently developed new Pd- and Ni-based precatalyst systems which avoid the problem of -elimination of primary and secondary alkyl groups: Terao, J. ; Kambe, M. Acc. Chem. Res. 2008, 41, 1545. (43) (a) Tamura, M. ; Kochi, J. J. Organomet. Chem. 1971, 31, 289. (b) Rollick, K. L. ; Nugent, W. A. ; Kochi, J. K. J. Organomet. Chem. 1982, 225, 279. (44) Cahiez, G. ; Lepifre, F. Ramiandrasoa, P. Synthesis 1999, 2138. (45) Hatakeyama, T. ; Nakamura, M. J. Am. Chem. Soc. 2007, 129, 9844. (46) Rueping, M. ; Ieawsuwan, W. Synlett 2007, 247. (47) Nagano, T. ; Hiyama, T. Org. Lett. 2005, 7, 491. (48) Cahiez, G. ; Chaboche, C. ; Mahuteau-Betzer, F. Org. Lett. 2005, 7, 1943. Scheme 3 special, but generally applicable, reaction conditions developed by Japanese workers45 have ? nally prov ided the possibility of clean aryl-aryl cross-coupling reactions in which competitive homocoupling of the aryl Grignard reagent has been almost completely suppressed.In this procedure an active catalyst system was prepared by addition of 18 mol % of C2H5MgBr in Organometallics, Vol. 28, No. 6, 2009 1605 A further improvement resulted when it was found that atmospheric oxygen could replace the 1,2-dihaloethane as oxidant in the homocoupling of aryl, vinylic, and alkynyl Grignard reagents using either Fe or Mn catalyst precursors. 49 As Tables 5 and 6 show, this procedure gave excellent results. The most recent contribution to iron-catalyzed cross-coupling, which appeared during the preparation of the ? al draft of this paper, involves application of the old one-pot Barbier procedure in which FeCl3 served as precatalyst and stoichiometric amounts of magnesium turnings and TMEDA additive were used. A mixture of an alkyl and an aryl bromide was added to the mixture of precatalyst, TMEDA , magnesium, and solvent at 0  °C. Good yields of cross-coupled products were obtained. 50 There has been a great deal of activity in the areas of Grignard reagent/organic halide cross-coupling and aryl Grignard reagent homocoupling, and the coverage in this essay, whose focus is on the historical aspects, is far from exhaustive.Attention is called to the 2005 review by Frisch and Beller51 and especially (49) Cahiez, G. ; Moyeux, A. ; Buendia, J. ; Duplais, C. J. Am. Chem. Soc. 2007, 129, 13789. (50) Czaplik, W. M. ; Mayer, M. ; von Wangelin, A. J. Angew. Chem. , Int. Ed. 2009, 48, 607. (51) Frisch, A. C. ; Beller, M. Angew. Chem. , Int. Ed. 2005, 44, 674. to the recent Accounts of Chemical Research special issue on cross-coupling. 52 Since ? st reported in 1943, the cross-coupling of Grignard reagents with organic halides, thanks to further development by many later workers, has become a broadly applicable, very useful reaction in organic synthesis. There is much more about Grign ard reagents that I have not covered: the various procedures used in their preparation, the mechanism of their formation (which is still controversial), the more complex organomagnesium compounds such as bis(cyclopentadienyl)magnesium, magnesium butadiene, and magnesium anthracene, and the many kinds of reactions that Grignard reagents have been reported to undergo.But this is only a short essay, and so I have been able to cover only a few selected topics, ones which I hope will be of interest to the reader. More information can be found in the books that I have cited earlier. 16 Acknowledgment. My thanks, as always, to Professor Arnold L. Rheingold for the cover ? gure. OM900088Z (52) Acc. Chem. Res. 2008, 41, No. 11, 1439-1564, special issue. A collection of 11 reviews, many of them relevant to the subject matter of the present essay, with useful, up-to-date references.

The Honest to Goodness Truth on Essay Samples by Esl Common Mistakes

The Honest to Goodness Truth on Essay Samples by Esl Common Mistakes Top Essay Samples by Esl Common Mistakes Secrets You will present facts so it doesn't just sound like you're ranting about your side of the matter. Neither is a great thing, since they're searching for people that are open to receiving new information from professors and not only deciding they know everything already. The point is to compose a paper supporting the side that you opt for. All you write needs one key idea. The Fundamentals of Essay Samples by Esl Common Mistakes Revealed Anyway, nowadays it is simple to locate a dependable essay writing company that will supply you with qualified guidance and can help you satisfy the deadlines. Therefore, proofreading is a crucial portion of the writing process which can help remove grammatical mistakes. To develop into a better writer, you've got to modify your thinking about editing. The revising procedure is essential to refine your work and make a masterpi ece. The New Angle On Essay Samples by Esl Common Mistakes Just Released After the text is divided into lots of more or less short paragraphs, each representing a comprehensive idea, it's easier understood and is more inclined to be read attentively. Possessing a very good error-free sample before you, it's possible to avert the errors. When you are just too verbose, you're using more words than needed. It is quite a bit easier to seek out an example that's written in the required format and follow it. New Questions About Essay Samples by Esl Common Mistakes There are not any grammar mistakes. There are an assortment of words and phrases that are typically confused and misused in sentences. As an overall guideline, in case you have a slightest doubt about the significance of a word, use your dictionary. It is a fact that you're a coward. Naturally, it is also going to indicate a few changes in the tense and voice. Sometimes students often begin writing in the very firs t person and change to the third individual. Writing is a skill you may work on for the remainder of your life. At Ameritech, it is a part of all of our curricula, because it's such a critical part of life. For instance, if you decide on present tense, all of your sentences have to be in the present. Unfortunately, you cannot combine two complete sentences with only a comma. A run-on sentence takes place when you connect two principal clauses without a punctuation. The very first sentence is a subject speedy food. Changing between verb tenses within a sentence can make it hard for the reader to obey a bit of writing and ought to be avoided. Topic sentences go at the start of each paragraph in which you are just about to explore a new topic (not at the conclusion of the prior paragraph). If you can't locate the principal concept, you have to re-write the very first sentence of the paragraph. If you can't explain the major idea in 1 sentence, perhaps you don't have one. The Essay Samples by Esl Common Mistakes Chronicles Keep in mind, no reader wishes to be lectured at. It is of the utmost importance to take note of your mistakes to be able to increase your general IELTS writing score. There's no student who'd say Academic writing is as simple as ABC. As an example, in India English is among the official languages. Even though some mistakes don't influence our students' capacity to communicate, we should always strive for greater accuracy. Some terrible topics show admissions officers w hich you don't have a fantastic awareness of judgment or maturity, which is a problem as they are building a category of college students who have in order to deal with independent life on campus. Academic writing, specifically, is an enormous challenge. Instead, search for certain errors that ESL students have a tendency to make. New Step by Step Roadmap for Essay Samples by Esl Common Mistakes Unfortunately, stumbling in the TMI zone of essay topics is more prevalent than you believe. At times, even when you're writing about an interesting, relevant subject, it's still possible to appear immature or unready for college life due to the direction you present that topic the way you really write your own personal statement. Improve your vocabulary and you'll be in a position to express your ideas more clearly. The exact same ideas must be briefly summarized in conclusion. While writing a part of academic text, it's almost always a fantastic idea to use the third person narrativ e. The title is a significant portion of the essay. Comparison words desire a comparison. In case you have troubles with it, you may use a tool likeBest Essays. An introductory phrase stipulates some background info and is generally followed by a comma. 1 conjunction for two clauses One conjunction is sufficient to join two clauses we don't usually use two. Alternatively it's possible to split both clauses utilizing a full-stop. Students always have a great deal of troubles with the correct use of commas with the compound subject. The New Angle On Essay Samples by Esl Common Mistakes Just Released Contraction of words is a significant tool in all sorts of writing. Search for different guides with tips on the most critical things to do to take, which is likely to make your paper sound good and be accomplished professionally. Contractions Words are occasionally shortened especially as soon as the writer ways to create an emphasis on an idea.

Why the Dominican Republic is in the Early Expanding Stage...

The Dominican Republic is a developing country in the early expanding stage of their demographic transition. This means their Crude Birth Rate (CBR) is constant, their Crude Death Rate (CDR) is decreasing exponentially, and their Rate of Natural Increase (RNI) is growing. All of these values correspond to the number of births per 1000, number of deaths per 1000, and population growth or the (CBR – CDR), is greater than zero indicating growth of population annually, respectively. These values of the Dominican Republic and more are shown below in comparison to the average values of the world. Indicator Dominican Republic World Average Population (mid-2013) 10.3 million 7,137 million Projected Population (mid-2050) 13.1 million 9,727†¦show more content†¦These are lower than the values of those of the world by .1% for these years, respectively. These values mean that sex education and contraception use were high and have effectively increased since 1995. This is crucial for a developing country because much of the population in other countries like Chad, Nigeria, and Cameroon have HIV/AIDS and thus are prone to more deaths because of it. This is because there is a large dearth in health care. As the percent of the population, 15-49, with HIV/AIDS decreases, the CDR will decrease and hopefully increase the population. The infant mortality rate (IMR) indicates the number of deaths for a person under the age of 1 per 1000 live births. The Dominican Republic’s IMR is 27 or 2.7%. This, in comparison to the world average, is significantly lower. This rate is caused by lack of healthcare, malnutrition and a low number in urban population. The more a popu lation is urbanized, the more access it has to proper food sources and healthcare and as a result, better off to survive. With a lower than average IMR, the Dominican Republic is effectively keeping a low CBR and can expect to see a decrease as more of the population transitions from rural to urban. Life expectancy at birth is a strong indicator of the quality of life and environment one is born in. If war, famine, and disease overtake a country, the population less likely to live a long and fulfilling life. A lifeShow MoreRelatedOne Significant Change That Has Occurred in the World Between 1900 and 2005. Explain the Impact This Change Has Made on Our Lives and Why It Is an Important Change.163893 Words   |  656 Pages161 6 Locating the United States in Twentieth-Century World History †¢ Carl J. Guarneri 213 7 The Technopolitics of Cold War: Toward a Transregional Perspective †¢ Gabrielle Hecht and Paul N. Edwards 271 8 A Century of Environmental Transitions †¢ Richard P. Tucker 315 About the Contributors †¢ 343 _ IN TR OD UC TIO N Michael Adas B y any of the customary measures we deploy to demarcate historical epochs, the twentieth century does not appear to be a very coherent Read MoreStephen P. Robbins Timothy A. Judge (2011) Organizational Behaviour 15th Edition New Jersey: Prentice Hall393164 Words   |  1573 Pages32 Ethical Dilemma Jekyll and Hyde 33 Case Incident 1 â€Å"Lessons for ‘Undercover’ Bosses† 34 Case Incident 2 Era of the Disposable Worker? 35 vii viii CONTENTS 2 2 The Individual Diversity in Organizations 39 Diversity 40 Demographic Characteristics of the U.S. Workforce 41 †¢ Levels of Diversity 42 †¢ Discrimination 42 Biographical Characteristics 44 Age 44 †¢ Sex 46 †¢ Race and Ethnicity 48 †¢ Disability 48 †¢ Other Biographical Characteristics: Tenure, Religion, Sexual Orientation

The Media and Public Figures - 903 Words

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Persuasive Essay Topics Writing - the Story

Persuasive Essay Topics Writing - the Story The Ultimate Persuasive Essay Topics Writing Trick At the exact same time, it's an amazing persuasive essay idea. You will find that several of the topics can be adapted to suit almost any sort of writing assignment. Your persuasive essay needs to have a very clear plan, which will provide you an opportunity to focus on the most important elements of the work and put aside all of the minor arguments. Just write down the critical points you wish to put in your essay and concentrate on developing them. Top Persuasive Essay Topics Writing Choices Qualities of an excellent persuasive essay topic The topic ought to be specific. Quite frequently, the very best topic is one which you truly care about, but you also will need to get ready to research it. Selecting an excellent topic for your essay is among the most significant and frequently tricky parts for many students. Possessing fantastic research abilities and selecting a superb topi c is vital. Every school has to have a sex education class. There are several persuasive essay topics to pick from to finish your high school or college assignment. Even a student can begin a business online. Students with good attendance has to be rewarded. First of all, you will need to comprehend the fundamental fundamentals of persuasive writing and know the five elements of persuasion. Any idea can prove to be a wonderful foundation for a topic. It is very important to pick a topic that you truly care about because you will likely enjoy writing and it's going to be less difficult for you to have a stand on such problem and defend your standpoint. Figure out which of the topics, you presently have a fairly good background on which will make it possible for you to have a relative edge. Persuasive essays are a fantastic means to encourage the reader to check at a particular topic in a different light. An argumentative essay requires you to choose a topic and have a po sition on it. It's important to understand that essay topics are just basic ideas that leave you pondering an idea that might be a huge deal to somebody else. Deciding upon a persuasive essay topic may take a great deal of time without ending up with the terrific solution. The Battle Over Persuasive Essay Topics Writing and How to Win It Before writing any form of academic paper, it is crucial to choose the subject, and the persuasive essay isn't the exception. Persuasive essay format differs in every specific instance, even though it has some common facets. Persuasive essays haven't any paragraph limits. A persuasive essay should adhere to a typical pattern if you would like it to be readable and clear. The Characteristics of Persuasive Essay Topics Writing In most high schools, your capability of writing this kind of essay is going to be evaluated in class. There are many persuasive essay examples college students are able to make use of online. Select the period of lif e that you believe is best and compose an essay arguing why it's the very best time of life. In fact, understanding how to compose a persuasive essay is a significant skill for students of various specialties. Before you commence working on the paper, you must go through several topics to compose a persuasive essay on. Most issues can have essays on all the aforementioned questions. You must settle on a persuasive essay topic that permits you to present the most effective possible case. The most effective persuasive speeches aren't written in a rush. When prior brainstorming is finished, you might begin drafting your essay. Be sure to define the objectives of your essay clearly because your essay is dependent upon your approach. Weave in your own perspective to make it unique. Every argumentative essay ought to have an opposing view which can help you to prove you're right. Always remember a great persuasive essay ought to be persuasive. Writing an outline is a must if you need your essay to have a crystal clear and understandable structure. Writing a persuasive essay demands a great deal more than the capability of convincing the readers. It is not an easy task to accomplish. Writing a superb persuasive essay is not a simple task, however, it's achievable.

Accounting Information System Business Requirement Processes

Question: Discuss about the Accounting Information System for Business Requirement Processes. Answer: Introduction The report presented here explains and describes a business B. Bakery. The B. Bakery business owners are not at all happy with their accounting workflow, and they are looking to adopt good accounting software to take up their business to the next level. The report describes the component and competence of accounting information systems and its internal control. The business requirement processes and the related technology or infrastructure, as well as the challenges, have been explicitly discussed in this presented report. The investment done by the Bakery owners have a clear objective that they should consider some of softwares that will give them the desired outcome or results they are looking for. The author has selected some of the suitable accounting software and provides a justification of why they need that software and how it will help the Bakery to solve their accounting issue. Overview of the business processes The B. Bakery has been in the firm for the past 50 years, and they have been supplying bread, biscuits, and other bakery products along with some confectionary products such as sweet, bonbons, etc. to several different businesses which include pub chains and supermarkets. The B. Bakery business is a family business and has a total of around 70 employees who are working for this bakery business. They have been doing this business for the past 50 years and have been doing well as far as the sales revenues concern because last year they made around $13.5 million in business. They do supply their bakery products to different markets. But for quite some time they have been facing challenges with the business performance and recently from the last few years they have been experiencing some business growth from their newly produce product ranges. But somehow during this processes they have lost their major accounts which cost them heavy as they were completely unable to provide some of thei r bakery products at a competitive rate or cost. As a result, they have hired an accounting professional to look after the business records, but somehow they feel that they need to have a much better option as far as the accounting is a concern. So they have decided to go with a software based system to look after their accounts which will help them to increase their business sales and generate revenues. They are seeking to invest in the software so as to help them with their business to take higher levels. Business Requirements It is true that all the processes in an organization or business are linked up with each other, and if any one process is affected then, it will affect the others too (Meshalkin and Katerishchuk 2014). Some indispensable processes need to be addressed and performed by the B. Bakery are: 1. Marketing 2. Sales 3. Accounting 4. Production Unit 5. Supply chain management 6. HR Management The above-discussed processes are vital processes as far as the B. Bakery business is a concern. But there are some other critical processes but among all those the account is an essential part of any organization or business (Recker 2015). Moreover, it has been reviewed that B. Bakery has been facing some significant challenges on their accounts and for that; they have already hired an accounting professional who handles all their account work. Moreover, the B. Bakery owners are not satisfied with the overall outcome and due to this; they have lost most of the business sales in previous years. So they have decided that they need accounting software which can help to make the workflow process smooth and did understand market researching and business processes. The information that they will gather will help the B. Bakery to prepare some strategy which will help them to improve the business efficiency and effectiveness in the coming years (Von Mnchhausen et al. 2014). All these proces ses that have been discussed are critical in any Bakery business, and if proper accounting software is implemented in the firm, this will help them. So the B. Bakery has decided that they will invest money to implement accounting software, and this will take their business to the next level for sure. Required outcome from these processes The B. Bakery does need various outputs from their primary business so that their efficiency and effectiveness does increase in the marketplace which will help them to achieve the desired result. The most important outcome they need is the data or information. The data or information that is mostly related to operational and transactional part is required because without it nothing can be processed or no better decision can be taking on the business (Batocchio et al. 2016). The information or data such as raw material and inventory cost, vendors cost total sales figure, labor and production charges, etc. All other information or data are critical as useful data related to salaries of the employees. So the decision of making the AIS implementation in the business will help the Bakery business to manage various activities such as process managing, auditing, tax consulting, financial accounts, etc (Weske 2012). The information does play a critical role in the business because without it we cannot do anything with respect to the any business and organization. If we review the below mentioned points we can understand some business requirements that needs to be fulfilled. The below mentioned points are some operational requirements of this business that needs to be fulfilled, and they are listed below accordingly. They are: 1. Improvement must be made to the accounts. 2. The accounting software needs to integrate with all the other bakery business processes. 3. The business can be able to make some right and better decision on the bakery business. 4. Implementation or integration of AIS in the bakery business. Determining the System Requirements or Needs There are some possible software functionalities and features that the B. Bakery should consider to meet the information technology objectives. The firm does need Accounting information system a system that will help the B. Bakery to collect, store and process the financial and accounting information or data which has been used by decision makers. It tracks the accounting activity in connection with IT resources. There is some internal or subsystem within the Accounting information system software such as reporting cycle, HR revenue cycle, financial and production cycle and a basic ledger (Hall 2012). There are some basic features and functionality of the business process, and they are mentioned below. 1. The AIS function is that the effective and efficient storage and collection of data or information concerning the business financial activities which includes getting the transaction information from the source documents, recording the information on operations in a journals and then posting those information or data from those journals to ledgers and within the ledger the data will be sorted out from different accounts. 2. The Accounting information system is to supply the data or information which is helpful for making the right decisions which include the productive managerial reports and statements related to finance (Lipi et al. 2015). 3. The Accounting information system will provide all the required internal control to ensure that the reliability of the data or information that is generated or created by the software implemented and moreover to make sure the business objective and activities efficiency are maintained. Selecting the Software for B. Bakery The selection of software is always a challenging task for any business and organization. As per the given case, it has been observed that we need to select an accounting information system that the met the requirements of the present B. Bakery business. There are different kinds of accounting software requirements such as Small, Mid, and large industry. Low-Level Software These kinds of low-end accounting software are mostly suitable for small businesses and most businesses which have only maximum 2 to 5 employees. This low-end software's capable of doing and delivers the necessary activities of financial accounting and reviewing the financial reports. The softwares such as Xero, Freshbooks, QuickBooks, SAGE 50, etc. Mid Level Software These kinds of mid-level accounting software are mostly suitable for medium size businesses and mostly businesses which have only maximum 50 to 100 employees (Rahman et al. 2015). This range of software's are highly capable of performing real critical tasks, and they are highly scalable and do perform some critical task to generate the accurate reporting of the transactional data or information. The software's such as QuickBooks (Enterprise), Microsoft Dynamics, SAGE 100 ERP 2015, CYMA, etc. are some of the mid-range softwares. High Level Software These kinds of high level accounting software are mostly suitable for large size businesses and mostly businesses which have more than 150 employees. This software is highly capable of performing some severe and critical accounting activity (Taipaleenmki and Ikheimo 2013). They have extended functionality and have the capability to solve significant accounting problems. Softwares related to them are Oracle, SAP, ERP X3 are some related softwares. Vendor selection The B. Bakery is a mid-level business where there is a total of 70 employees are working altogether. So based on the previous question no. Four we can select the mid-level accounting software and can discuss two different accounting software packages and their functionalities (Fulmer and Gerard 2014). It will help the B. Bakery to have a proper idea of which software they need to select. So the right vendors for B. Bakery can be chosen by any of these software packages. They are QuickBooks (Enterprise), Microsoft Dynamics, SAGE 100 ERP 2015, CYMA, etc. Let us compare two different software packages to understand their features to select the right vendor for B. Bakery (Zimmerman 2015). Below there are two software packages that have been compare and contrasts, and a detailed explanation have been provided below about the software and why it is suitable for the mid-level business. SAGE 100 ERP One of the best features of SAGE 100 ERP is that it can provide you multiple options of Accounting Information System (AIS) software for small and medium business (Sage 2012). Few of them are mentioned below such as 1. SAGE 100 Advanced ERP 2. SAGE 100 Standard ERP This software is highly scalable in various businesses processes. This software's are capable of handling a large number of users in a single period for different kinds of business activities such as HR, CRM services, financial and accounting BI (Business Intelligence) and many such activities. It is highly flexible, stable and modern. It can be integrated into the client's server or on any platform which is online (Yes 2015). These involve the capability to provide the paperless office delivery choices; it provides the direct access to the paperless office viewer and enhances the performance of printing to print a huge variety of registers and reports. These needs Microsoft SQL and MS Windows based backend database. It is user-friendly to use and understand (Woodward 2014). The software can be highly modifies that the client or user can purchase and integrate features as needed. It saves history budgets while creating budgets for future periods. Creating the financial statement by c hoosing from various ranges of an inbuilt time. Microsoft Dynamics The software does optimize your sales process and improves the efficiency of B. Bakery sales team, as it gives an integrated view of the business and clients details. Using the extreme knowledge and tools which helps to enhance the business close rates and which also helps the B. Bakery team to sell the right product at the right time (Kachinske and Kachinske 2014). The software improved the efficiency of marketing events or programs and also controls the first performance indicators intuitive tools for the division and campaign management and in-depth marketing analysis. There are different variations they are SL, GP, and NAV. Among all those different variations the MS Dynamics GP is necessary software that provides the features for finance, controlling resources and the decisions (Duncan and Liley 2013). The MS Dynamic NAV is used for a general purpose for any medium sized business and does provide a complete control over the core business such as reporting, BI (Business Intellige nce), Supply Chain Management, Financial Management and HRM, etc. MS Dynamics SL is the third version of it, and this is also used for a mid-level business, and the best feature of this software is that it is suitable activity related to construction. It does provide the high quality support service to their customers (Shankar et al. 2014). The complete history of the cases related to the support enabling them to provide the support in a stable way for greater customer loyalty and enhancing the future profitability. Selecting most suitable vendor for B. Bakery Business B Bakery needs customized software's named as AIS for investment purpose. They want the software applications to work on an intercepted format platform that connects all organizational management. It must be strictly recommended to use the SAGE 100 ERP applications that are used for accounting software purpose for business applications (Automation 2014). The combined supported platform will be available through the software application. The clients, customers, and the vendors used to connect the same differentiated system using web based interface system. The transformation of raw business data into some meaningful advantage will add some extra knowledge to the existing business process (Payable et al. 2012). There must be an integrated software applications system for the firm management perspectives with the modular fundamentals of SAGE 100 ERP. These vital data and information may help the organizational management to create a strategy of competency. The billing payment modular st ructural software applications must be required for the corporate management. The mobile electronic commerce has become a trend. It is strictly advisable to maintain and manipulate the sales module in the SAGE 100 ERP applications which may assist the business organization to move towards future upcoming. It is strictly recommended to earn more company revenues if the management may utilize the accounting software calmly. Receiving the proper rate of interest will be further improved and hence, be faster in future upcoming. In these regards, it is strictly recommended that the expansion of customer base and segmentation that will be more scope for the business perspectives. The company management must maintain fulfillment to be sorely organized and efficient. It is strictly advisable to sustain and manipulate the sequence and scalability of the platform seamlessly. The compulsion billing payment modular fundamental software applications must be required for the organizational management. The organization management must maintain the sequence of the operational and transactional data and information in a perspective manner. In this regards, many multinational companies tend to face extreme pressure regarding customer base segmentation and handling the accounting software applications (Haddara 2014). The researcher wants to recommend that the maintain ace of the software dashboard must be manipulated ad equately and by the top and qualified experts; to avoid misrepresentation of data and information. As the analysis helps in understanding potential customers, understanding customers requirements thus customer relationship management will be easier and better. It must be strictly recommended to use the SAGE 100 ERP applications that are used for accounting software purpose for business applications. Conclusion The report discusses about B. Bakery accounting issue and solving it by implementing the accounting software in the firm. The report consists of the explanation of the bakery business and explains what the exact issues are. The issue is addressed, and various software levels are discussed in this document. The report does provide the functionalities of the selected software's and do compare what they have to offer to the mid-level size business. The authors provide a detailed recommendation for the bakery business of which software to be selected at last. The overall idea of this report is to suggest the accounting software that needs to be implemented in the bakery business to improve the business to the next level. References Automation, S.T., 2014. Sage Sales Tax. Sage, 866, pp.996-7243. Batocchio, A., Ghezzi, A. and Rangone, A., 2016. A method for evaluating Business Models Implementation Process. Business Process Management Journal, 22(4). Duncan, D. and Liley, C.J., 2013.Microsoft Dynamics GP 2013 Reporting. Packt Publishing Ltd. Fulmer, B.P. and Gerard, G.J., 2014. Selecting an Enterprise Resource Planning System: An Active Learning Simulation. Journal of Emerging Technologies in Accounting, 11(1), pp.71-82. Haddara, M., 2014. ERP Selection: The SMART Way. Procedia Technology, 16, pp.394-403. Hall, J., 2012. Accounting information systems. Cengage Learning. Kachinske, E. and Kachinske, T., 2014. Maximizing your sales with Microsoft Dynamics CRM 4.0. Cengage Learning. Lipi, I., Rama, R. and Agaraj, X., 2015. Implications of Accounting Information System Implementation in SMEs: A Study on Retail Business in Vlore Region.Mediterranean Journal of Social Sciences,6(3), p.553. Meshalkin, V.P. and Katerishchuk, M.Y., 2014. Effective Business Processes Reengineering on the Bakery Enterprises.International Journal of Advanced Studies,4(2), pp.3-8. Payable, A., Receivable, A. and Ledger, G., 2012. Sage 100 ERP I Customer Success. Sage, 866, pp.530-7243. Rahman, M.M., Ahammed, M., Uddin, M., Rouf, M. and Uddin, M.M., 2015. Obstacles and Implementation of Accounting Software System in Small Medium Enterprises (SMEs): Case of South Asian Perspective. Abdur and Uddin, Mohammad Main, Obstacles and Implementation of Accounting Software System in Small Medium Enterprises (SMEs): Case of South Asian Perspective (May 23, 2015). Recker, J., 2015. Evidence-based business process management: Using digital opportunities to drive organizational innovation. In BPM-Driving Innovation in a Digital World (pp. 129-143). Springer International Publishing. Sage, C.R.M., 2012. Sage 100 ERP.Sage,888, pp.995-6464. Shankar, C., Bellefroid, V. and Thakkar, N., 2014. Customer Success with Microsoft Dynamics Sure Step. Packt Publishing Ltd. Taipaleenmki, J. and Ikheimo, S., 2013. On the convergence of management accounting and financial accountingthe role of information technology in accounting change. International Journal of Accounting Information Systems, 14(4), pp.321-348. Von Mnchhausen, S., Hring, A.M. and Schulz, K., 2014. Strategies for medium-sized values-based food chains during growth processes. Weske, M., 2012. Business process management: concepts, languages, architectures. Springer Science Business Media. Woodward, J., 2014. Tips and tricks for getting the best ROI from your Sage 100 ERP system.Sage,11, p.18. Yes, Y.Y.Y.Y., 2015. Sage 100 Supported Versions.Sage. Zimmerman, J.L., 2015. The role of accounting in the 21st century firm. Available at SSRN 2544697.

Normans And Middle English Essays - English Languages, Phonology

Normans And Middle English The year 1066 had a resounding impact on the course of English history. William the First, Duke of Normandy, conquered England and took it as a stronghold in his reign. The French rule over England lasted for several centuries and brought about innumerable changes to the English state, language, culture and lifestyle. William imported French rulers to take over English government and religious posts. The French were not only the new aristocracy in England, but the new society. The English amended their language and their culture in an effort to more resemble the French and to communicate with their new lords. The English language was more changed by the Norman Conquest than by any other event in the course of English history. Middle English is defined as the four hundred year period between the Norman Conquest and the time the printing press was introduced to England in 1476. This essay will explore the specific effects that the French had on Middle English morphology, phonology, syntax, semantics and lexicon. During the period of French rule in England the standing of English as a valid language dropped substantially as French took over as the status language. Because so much of the French influence has been nativized by present-day speakers, many do not realize the impact that our language took in the years following 1066. Not one aspect of English life went untouched by the Norman presence in England, notably, its language. Phonology In addition to introducing new words into the English language, the Normans also introduced some new sounds. The English had previously had no phonemic distinction between /f/ and /v/; /v/ was merely an allophone of /f/ that occurred between vowels. However, with the influx of French loans which began in /v/ and contrasted as minimal pairs in English, this distinction made its way into Middle English: French loans English vetch fetch view few vile file The French also influenced the adoption of several new diphthongs into English. Diphthongs are two vowel sounds which are pronounced as one. Diphthong Old French Old English /eu/ neveu neveu (nephew) /au/ cause cause /Ui/ bouillir boille (boil) point point / i/ noyse noise choisir chois (choice) The new English diphthongs were not exactly like they were in French - they were modified by existing English vowels to create brand new diphthongs. The stress pattern of Old French words differed from that of Old English words, and often both stress patterns were present. Germanic languages, such as English, tends to place primary stress on the first syllable, unless that syllable is an unstressed prefix. French, on the other hand, prefers to stress the heavy syllable (one containing a coda) closest to the end of the word. Middle English loans from French often retained their native stress pattern, however, in Present-Day English, the majority of these borrowed words have conformed to the Germanic pattern. Lexicon Irrefutably, the largest influence that the Normans had on the English language was on its vocabulary. From the time William usurped the English throne until the end of the Middle English period, our language was inundated with French vocabulary terms. In fact, of the 2,650 words in the epic English poem "Sir Gawaine and the Green Knight," at least 750 are estimated to be of French origin. Even in Present-Day English, some of our most commonly used words are of French origin; table, tax, religion, trouble and pray are all derived from French words borrowed into Middle English. Hardly one syntactic category was left untouched by French loan-words during Middle English, although the majority of English words borrowed from Old French tended to be nouns, verbs and adjectives. The following is a very brief sample of some now-common words which had recently joined English in the Middle English period: Adjectives: inequales ?inequal,' principalis ?principal,' naturales ?natural' Verbs: strive, please, waste, join, cover Prepositions: French contributed to the constructions of according to and during Interjections: gramercy ?thank you' Nouns: ancestor, cellar, dinner, garment, kennel, music, noun, plague, statute The French gave the English language many specialized words, such as those used in culinary or legal situations. Because the Normans had taken over judicial and aristocratic roles, their high-prestige vocabulary was passed on to the lower-class English who acted as their clerks and servants. Thus, many cooking terms such as broil, goblet, and beverage were passed on by masters to their servants. The French influence on the lexicon was nearly nonexistent in areas where the French masters would have had little or no contact with their servants, for example, in the field.