Regioselective Alkylation of Lithium Dienediolates of α,β-Unsaturated Carboxylic Acids
作者:Eva M. Brun、Salvador Gil、Ramón Mestres、Margarita Parra
DOI:10.1055/s-2000-6323
日期:——
Lithium carboxylic acids dienediolates are regioselectively alkylated at the α-carbon by reaction with tosylates derived from both primary and secondary alcohols. Both regio- and diastereoselectivity are improved when compared with those obtained in the corresponding alkylation with alkyl halides.
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.
Asymmetric hydrogenation of trisubstituted acrylic acids catalyzed by a chiral (aminoalkyl)ferrocenylphosphine-rhodium complex