Mild Pd(OAc)2/PPh3 Catalyzed Cyclization Reactions of 2-Vinylazetidines with Heterocumulenes: An Atom-Economy Synthesis of Tetrahydropyrimidinone, Tetrahydropyrimidinimine, and Thiazinanimine Analogs

Abstract

A versatile method for the reaction of N-alkyl-2-vinylazetidines with heterocumulenes has been established using a Pd(OAc) 2 /PPh 3 catalyst system at room temperature. Minor modifications in the design of either substrate allowed for the optimization of product yield. Evidence for p-allylpalladium formation was obtained from the reaction of trans-1-butyl-4-methyl-2-vinylazetidine, which afforded a cis/trans mixture of products arising from stereochemical inversion through h 3 -h 1 -h 3 isomerization.