New stereoselective synthesis of trans-2,5-disubstituted pyrrolidines by cyclization of aminyl radicals generated from 2- and/or 5-substituted N-chloro-N-alkylalk-4-enylamines with Bu3SnH-azoisobutyronitrile

Abstract

trans-N-Alkyl-2- and/or 5-substituted pyrrolidines are stereoselectively formed in up to 63% yields by N-chlorination of 2- and/or 5-substituted N-methylpent-4-enylamine with N-chlorosuccinimide, followed by heating a solution of the resulting N-chloro-unsaturated amines in benzene with Bu₃SnH–azoisobutyronitrile under reflux; a pathway involving stereoselective cyclization of neutral aminyl radicals is proposed.