Synthesis of cyclic amines and allylic sulfides by phenylthio migration of β-hydroxy sulfides

Abstract

Rearrangement of β-hydroxy sulfides proceeds stereospecifically with capture of the episulfonium ion by the nitrogen atom of an amide. Almost quantitative yields of substituted pyrrolidines are obtained using a sulfonamide as the intramolecular nucleophile and with activation by trimethylsilyl trifluoromethanesulfonate (TMSOTf). With a free amine no cyclization takes place, but instead allylic sulfides are formed.