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The Michael reaction or Michael addition is the nucleophilic addition of a carbanion or another nucleophile to an α,β-unsaturated carbonyl compound. It belongs to the larger class of conjugate additions. This is one of the most useful methods for the mild formation of C–C bonds.〔(Michael Addition | PharmaXChange.info )〕 Many asymmetric variants exist.〔(【引用サイトリンク】 author = Hunt, I. )〕 : In this scheme the R and R' substituents on the nucleophile (a Michael donor) are electron-withdrawing groups such as acyl and cyano making the methylene hydrogen acidic forming the carbanion on reaction with base B:. The substituent on the activated alkene, also called a Michael acceptor, is usually a ketone making it an enone, but it can also be a nitro group. == Definition == As originally defined by Arthur Michael, the reaction is the addition of an enolate of a ketone or aldehyde to an α,β-unsaturated carbonyl compound at the β carbon. A newer definition, proposed by Kohler,〔Kohler. (J. Am. Chem. Soc., 1907, 37, 385; ibid., 1935, 57, 1316.〕 is the 1,4-addition of a doubly stabilized carbon nucleophile to an α,β-unsaturated carbonyl compound. Some examples of nucleophiles include beta-ketoesters, malonates, and beta-cyanoesters. The resulting product contains a highly useful 1,5-dioxygenated pattern. Classical examples of the Michael reaction are the reaction between diethyl malonate (Michael donor) and diethyl fumarate (Michael acceptor), that of mesityl oxide and diethyl malonate, that of diethyl malonate and methyl crotonate, that of 2-nitropropane and methyl acrylate, that of ''ethyl phenylcyanoacetate'' and acrylonitrile and that of nitropropane and methyl vinyl ketone. The Michael addition is an important atom-economical method for diastereoselective and enantioselective C–C bond formation. A classical tandem sequence of Michael and aldol additions is the Robinson annulation. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Michael reaction」の詳細全文を読む スポンサード リンク
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