Enantiomerically pure 2,2-dibromocyclopropanecarboxylic acids, simple chiral building blocks
作者:Mark S. Baird、Peter Licence、Viacheslav V. Tverezovsky、Ivan G. Bolesov、William Clegg
DOI:10.1016/s0040-4020(99)00048-4
日期:1999.2
Simple chiralbuildingblocks 1-(R)- and 1-(S)-2,2-dibromocyclopropanecarboxylic acids and 2-(R)-bromo-1-(S)-cyclopropanecarboxylic acids and their 1-methyl analogues, have been obtained on a preparatively useful laboratory scale.
Synthesis of (2S, 3R, 4S)-3,4-methanoproline and analogues by cyclopropylidene insertion
作者:Viacheslav V. Tverezovsky、Mark S. Baird、Ivan G. Bolesov
DOI:10.1016/s0040-4020(97)00988-5
日期:1997.10
Intramolecular insertion of single enantiomers of cyclopropylidenes into 5,6-related CH bonds adjacent to nitrogen has been used to obtain enantiomerically pure methanoproline and a number of analogues with a high degree of one- or two-fold asymmetric induction.
A general and efficient method for the preparative resolution of alpha- and beta-bromocyclopropylcarboxylic acids has been developed. This protocol involves a sequence of two crystallizations with pseudo-enantiomeric amines, cinchonine, and cinchonidine, which yield both enantiomers of the acid in highly enriched form. Both alkaloids can be easily recovered and reused multiple times without any loss of efficacy. (C) 2014 Elsevier Ltd. All rights reserved.