A Lewis acid activated reaction of Zn with EtI to promote highly enantioselective alkyne additions to aldehydes†
Abstract
An easily available BINOL–Ti(OiPr)4 catalyst system is found to activate the reaction of Zn powder with EtI for the asymmetric alkyne addition to aldehydes at room temperature. It allows the synthesis of a number of synthetically useful chiral propargylic alcohols with both high yields and high enantioselectivity (up to >96% ee).