Diastereoselectivity Control in Formal Nucleophilic Substitution of Bromocyclopropanes with Oxygen- and Sulfur-Based Nucleophiles
作者:Joseph E. Banning、Anthony R. Prosser、Bassam K. Alnasleh、Jason Smarker、Marina Rubina、Michael Rubin
DOI:10.1021/jo200368a
日期:2011.5.20
diastereoconvergent formal nucleophilic substitution of bromocyclopropanes with oxygen- and sulfur-based nucleophiles is described. The reaction proceeds via in situ formation of a highly reactive cyclopropene intermediate and subsequent diastereoselective addition of a nucleophile across the strained C═C bond. Three alternative means of controlling the diastereoselectivity of addition have been demonstrated:
描述了基于氧和硫的亲核试剂对溴环丙烷的非对映收敛形式亲核取代。该反应通过原位形成高反应性的环丙烯中间体并随后通过应变的C═C键非对映选择性地添加亲核试剂而进行。已经证明了三种控制加成的非对映选择性的替代方法:(1)热力学驱动可烯丙基羧酰胺的差向异构化;(2)通过大取代基的空间控制;和(3)羧酰胺或羧酸酯官能团的导向作用。