Diastereoselectivity in the formation of bicyclic cyclopropane carboxylic acid lactones
作者:Z Hell
DOI:10.1016/s0040-4020(98)01109-0
日期:1999.1.29
The intramolecular cyclization of malonic acid allylic esters yields bicyclic cyclopropane carboxylic acid lactones in a phase transfer catalysed reaction. The substituents of the allylic moiety and the reaction temperature influence the diastereomeric composition of the products.
A highly chemo- and enantioselectiveorganocatalyticcyclopropanation of α,β-unsaturated aldehydes with bromomalonate and 2-bromoacetoacetate esters is presented. The reaction is catalyzed by chiral amines and gives access to 2-formylcyclopropanes in high yields and up to 99 % ee.