Enantio- and diastereoselective synthesis of 2,5-disubstituted pyrrolidines through a multicomponent Ugi reaction and their transformation into bicyclic scaffolds
A new enantio- and diastereoselectivesynthesis of 2,5-disubstituted pyrrolidines through a multicomponent approach has been developed, using highly reactive pyrrolines 4 as preformed cyclic imines. The pyrrolidines obtained using protected aspartic acid as acid component in the Ugi condensation have been transformed into two epimeric bicyclic lactones 18, 19, which may find an application as external
An efficient and convergent Ugi synthesis of enantiomerically pure N-acyl-2,5-disubstituted pyrrolidines was coupled with an appropriate secondary transformation to give two series of bicyclic derivatives, namely hexahydro pyrrolo-oxazocinediones and -diazepinediones. (c) 2007 Elsevier Ltd. All rights reserved.