Enantioselective α-alkylation of unsaturated carboxylic acids using a chiral lithium amide
作者:Eva M. Brun、Salvador Gil、Margarita Parra
DOI:10.1016/s0957-4166(01)00152-5
日期:2001.4
The regio- and stereochemistry of the alkylation of dienediolates from unsaturated carboxylic acids with benzylic halides, which often results in mixtures of isomers, can be controlled by means of changes in the lithium amide, allowing the α-regioisomer to be obtained as the major diastereoisomer. In addition, when chiral amines are used, moderate enantiomeric excesses can be attained.
Lithium enediolates and dienediolates of carboxylic acids in synthesis: Alkylation with secondary halides
作者:Eva M. Brun、Salvador Gil、Ramón Mestres、Margarita Parra
DOI:10.1016/s0040-4020(98)00957-0
日期:1998.12
High yields in the alkylation of dianions of alpha,beta-unsaturated carboxylic acids with secondary halides can be obtained despite elimination reactions occurring. alpha-Regioselectivity for the alkylation of but-2-enoic acids (1-4) is seldom obtained. Although double bond stereoselectivity is higher than 99% for gamma-alkylated products, stereoselectivity is rather poor for most of the alpha-alkylated products. (C) 1998 Elsevier Science Ltd. AII rights reserved.