Asymmetric Vinylogous Aldol Reaction of Silyloxy Furans with a Chiral Organic Salt
作者:Ravi P. Singh、Bruce M. Foxman、Li Deng
DOI:10.1021/ja103331t
日期:2010.7.21
significance there is a general lack of asymmetric vinylogous aldolreactions that tolerate variations of both the silyloxy furans and aldehydes. We have developed a newchiral organic catalyst based on a carboxylate-ammonium salt preparedfrom a thiourea-amine and a carboxylic acid. This newcatalyst enabled us to develop an efficient asymmetric vinylogous aldolreaction of unprecedented scope with respect
Enantioselective Addition of 2-(Trimethylsilyloxy)furan to Aldehydes Using Cr(salen) as Catalyst. Effect of Water on Enantioselectivity
作者:Yuko Matsuoka、Ryo Irie、Tsutomu Katsuki
DOI:10.1246/cl.2003.584
日期:2003.7
Cationic (R,R)-Cr(salen) complex 2 was found to catalyze enantioselective addition of 2-(trimethylsilyloxy)furan to aldehydes to give 5-substituted butenolides, though diastereoselectivity was only modest. The presence of a small amount of water is essential for achieving high enantioselectivity.