Synthesis of 2‐Phenyl‐ and 2,2‐Diarylpyrrolidines through Stevens Rearrangement Performed on Azetidinium Ions

Abstract

AbstractA set of azetidinium ions substituted at the nitrogen atom either by a benzyl group or a benzhydryl group were synthesized to delineate the scope of their ring expansion into 2‐phenyl‐ or 2,2‐diaryl‐pyrrolidines through a Stevens rearrangement. Whereas the regioselectivity of the rearrangement is very high, the diastereoselectivity is low when 2,3‐disubstituted pyrrolidines are produced, except in one case. The major undesirable side‐reaction is a Hofmann elimination leading to ring cleavage.