Modulating steric effects in diastereoselective Staudinger reaction: Synthesis of optically pure cis-β-lactams
作者:M. Jayaraman、V. Srirajan、A.R.A.S. Deshmukh、B.M. Bhawal
DOI:10.1016/0040-4020(96)00048-8
日期:1996.3
Diastereoselection in the synthesis of β-lactams (14 and 15) via ketene-imine cycloaddition (Staudinger reaction) using different chiral auxiliaries has been examined. While sterically demanding imines derived from bicyclic aldehyde (1) with a β chiral centre provided excellent selectivity, use of imines derived from bicyclic aldehyde (17) with a γ chiral centre was not effective. Improvement of stereoselectivity
已经研究了使用不同的手性助剂通过乙烯酮-亚胺环加成反应(Staudinger反应)合成β-内酰胺(14和15)的非对映选择性。尽管在空间上需要具有手性中心为β的双环醛(1)的亚胺具有出色的选择性,但使用具有手性中心为γ的双环醛(17)的亚胺是无效的。还寻求使用衍生自手性胺(2d,e)和手性醛(1)的亚胺(6和7)来改善立体选择性。1中手性助剂的双环类萜骨架通过四氧化钌氧化将其分解,以良好的产率得到多官能化的β-内酰胺23a-d。