An expedient synthesis of N-acceptor-substituted 2,3-dihydropyrrols from the corresponding 2-pyrrolidinones

The title compounds 1 were prepared from the corresponding N-acceptor substituted 2-methoxypyrrolidines 3 by elimination with trimethylsilyl trifluoromethanesulfonate (TMSOTf) and N,N-di-iso-propyl ethyl amine (6 examples, 57–84% yield). The enantiomerically pure N-methoxy-carbonyl protected elimination substrates 3aa and 3ab were synthesized from the L-pyroglutamic acid derived pyrrolidinones 6a and 6b in three steps (80–83% yield overall).