Asymmetric three- and [2 + 1]-component conjugate addition reactions for the stereoselective synthesis of polysubstituted piperidinones
作者:Stephen G. Davies、Paul M. Roberts、Andrew D. Smith
DOI:10.1039/b701226h
日期:——
The efficiency and stereoselectivity of the conjugate addition of lithium (Z)- or (E)-beta-amino ester enolates, generated by lithium amide conjugate addition to an alpha,beta-unsaturated ester or deprotonation of a beta-amino ester, respectively, to a range of alpha,beta-unsaturated acceptors has been investigated. Deprotonation of a beta-amino ester with LDA, followed by conjugate addition to a chiral
(Z)-或(E)-β-氨基酯锂烯醇盐共轭加成的效率和立体选择性,分别通过酰胺锂共轭物添加到α,β-不饱和酯或β-氨基酯的去质子化而产生,已经研究了一系列α,β-不饱和受体。用LDA对β-氨基酯进行质子化,然后缀合到手性α,β-不饱和恶唑烷酮上,具有很高的2,3-抗选择性(约90%de),经氢解和纯化至均质,生成立体定义的三取代哌啶子酮立体异构体。由锂酰胺共轭物加成引发的α,β-不饱和酯与亚丙二酸丙二酸酯的不对称三组分偶联以高水平的2,3-抗立体选择性进行,