Cinchona Alkaloid‐Derived Zwitterions Catalyzed Enantioselective Steglich Rearrangement and Aldol Reaction of O‐Acylated Oxindoles

Abstract

AbstractA class of cinchona alkaloid‐derived zwitterions has been successfully applied to achieve highly enantioselective Steglich rearrangement. A series of O‐acylated oxindoles afforded C‐acylated oxindoles possessing a quaternary stereocenter. These products were obtained in high yields and with excellent enantioselectivity. The same catalytic protocol was also found to be applicable in the asymmetric aldol reaction of oxindoles. Studies were conducted to elucidate a clearer mechanism. These findings will advance the development of new reaction protocols that exploit cinchona alkaloid‐derived zwitterions as asymmetric nucleophilic catalysts.