Concise Formal Synthesis of (−)-Peduncularine via Ring-Closing Metathesis

Abstract

[reaction: see text] A synthesis of the 6-aza[3.2.1]bicyclooctene (-)-2 has been completed by a short sequence of reactions that required only six operations from (S)-malic acid and featured a novel ring-closing metathesis to form the bridged bicyclic ring. Because 2 was previously converted into (-)-peduncularine (1), its preparation constitutes a formal enantioselective synthesis of 1.