Synthesis of Enantiopure Substituted Piperidines <i>via</i> an Aziridinium Ring Expansion

Abstract

Herein we report a novel methodology for the asymmetric synthesis of 3-substituted piperidines from readily available chiral building blocks. This method, which features a novel irreversible dihydropyrole-tetrahydropyridine ring expansion, allows the introduction of a large variety of substituents at the 3-position and permits substitution at the 2- and 6-position giving mono-, di-, or trisubstituted piperidines with high diastereocontrol.