Regioselective and Asymmetric Diels−Alder Reaction of 1- and 2-Substituted Cyclopentadienes Catalyzed by a Brønsted Acid Activated Chiral Oxazaborolidine
作者:Joshua N. Payette、Hisashi Yamamoto
DOI:10.1021/ja0735958
日期:2007.8.1
Cationic oxazaborolidine 2 affords Diels−Alder adducts of ethyl acrylate and 2-substituted cyclopentadienes, derived from the corresponding mixture of regioisomers, as single isomers in excellent yields and enantioselectivities. Furthermore, Diels−Alder adducts of 1-substituted cyclopentadienes are obtained through a one-pot procedure whereby ethyl acrylate is initially employed to consume all 2-substituted