We report herein the enantioselectiveCu-catalyzed conjugate addition of organometallic reagents to sensitive Michael acceptors and their application to the synthesis of relevant target molecules. This is one of the most important methodologies to form a C-C bond in an enantioselective manner. A wide range of alpha,beta-unsaturated aldehydes and beta,gamma-unsaturated-alpha-ketoesters has been successfully
The first asymmetric Cu-catalyzed conjugate addition of dialkylzinc zinc reagents to a large scope of enals in presence of phosphoramidite, SimplePhos, or (R)-BINAP ligands with enantiomeric excesses up to 90% is reported. Moreover, ACA of Grignard reagents afforded moderate to good 1,4-regioselectivities with enantioselectivities up to 90%.
Reactivity and regio- and enantioselectivities were strongly dependent on reaction conditions and substrates. Good to excellent regio- and enantioselectivities were obtained with zinc reagents R2Zn and aluminum reagents R3Al. However, the asymmetric conjugate addition of Grignard reagents afforded only moderate to good regio- and enantioselectivities. β-Substituted aldehydes constitute a very important
Hydride reduction of alpha, beta-unsaturated carbonyl compounds using chiral organic catalysts
申请人:MacMillan David
公开号:US20060161024A1
公开(公告)日:2006-07-20
Nonmetallic, chiral organic catalysts are used to catalyze the 1,4-hydride reduction of an α,β-unsaturated carbonyl compound. The α,β-unsaturated carbonyl compound may be an aldehyde or cyclic ketone, and the hydride donor may be a dihydropyridine. The reaction is enantioselective, and proceeds with a variety of hydride donors, catalysts, and substrates. The invention also provides compositions effective in carrying out the 1,4-hydride addition of α,β-unsaturated carbonyl compounds.
作者:Stéphane G. Ouellet、Jamison B. Tuttle、David W. C. MacMillan
DOI:10.1021/ja043834g
日期:2005.1.1
The first enantioselectiveorganocatalytic hydride reduction has been accomplished. The use of iminium catalysis has provided a new organocatalytic strategy for the enantioselectivereduction of beta,beta-substituted alpha,beta-unsaturated aldehydes to generate beta-stereogenic aldehydes. The use of imidazolidinone 2 as the asymmetric catalyst has been found to mediate the transfer of hydrogen to a
第一次对映选择性有机催化氢化物还原已经完成。亚胺催化剂的使用为β,β-取代的α,β-不饱和醛的对映选择性还原生成β-立体醛提供了一种新的有机催化策略。已发现使用咪唑烷酮 2 作为不对称催化剂可介导氢从 Hantzsch 乙酯到一大类烯醛底物的转移。催化剂 2 在选择性 E-烯烃还原之前加速 EZ 异构化的能力允许在这个操作简单的协议中实施几何不纯的烯醛。