Rhenium-Catalyzed Regio- and Stereoselective Addition of Imines to Terminal Alkynes Leading to N-Alkylideneallylamines
journal contributionposted on 30.05.2012, 00:00 by Yoshiya Fukumoto, Masato Daijo, Naoto Chatani
The reaction of terminal alkynes with imines using ReBr(CO)5 as a catalyst results in the production of N-alkylideneallylamines and not the conventional propargylamines. The substituent on the imine nitrogen is important, and a diphenylmethyl group gave the best result. The catalytic cycle of this regioselective C–C bond forming reaction appears to involve the formation of an alkynyl rhenium species and subsequent nucleophilic attack of the alkynyl β-carbon atom on the imine carbon to give a vinylidene rhenium species.