Domino Reaction of Pyrrolidinium Ylides: Michael Addition/[1,2]-Stevens Rearrangement.

A novel domino reaction featuring a Michael addition/[1,2]-Stevens rearrangement reaction of pyrrolidinium ylides with electrophilic alkenes is described. Ylides generated under mild conditions from 2-aryl- N-cyanomethyl- N-methylpyrrolidinium salts entered the Michael addition, followed by a [1,3]-hydrogen shift and finally the [1,2]-Stevens rearrangement to give 3-aryl-2-cyano-2-(2-EWG-ethyl)-1-methylpiperidines.