Abstract

A direct route to erythrinanes has been completed by a sequence that involves diastereoselective conjugate addition on a α,β-unsaturated lactam, followed by a ring-closing metathesis reaction to construct ring A. The synthesis of the key intermediates C-10b functionalized dihydropyrroloisoquinolines is achieved via Parham cyclisation and α-amidoalkylation reactions.

Keywords: erythrina alkaloids, amidoalkylation, conjugate addition, lithiation, ring-closing metathesis