Abstract:In the past decade ring expansion of aziridines and aziridiniums fused to other rings has developed into an attractive alternative method to classical pyrrolidine, piperidine and azepine ring construction approaches. This short review provides an update on recent reports and demonstrates the usefulness and the efficiency of this approach.
“…The ring expansion of pyrrolidines to piperidines via an aziridinium intermediate under kinetic and thermodynamic conditions is well-established [23,24,25,26,27,28]. This method was used to access piperidines 30 , 30′ from prolinols 29 , 29′ .…”