The Enantioselective Synthesis of Eburnamonine, Eucophylline, and 16′‐epi‐Leucophyllidine

A synthetic approach to the heterodimeric bisindole alkaloid leucophyllidine is disclosed herein. An enantioenriched lactam building block, synthesized through palladium‐catalyzed asymmetric allylic alkylation, served as the precursor to both hemispheres. The eburnamonine‐derived fragment was synthesized through a Bischler–Napieralski/hydrogenation approach, while the eucophylline‐derived fragment was synthesized by Friedländer quinoline synthesis and two sequential C−H functionalization steps. A convergent Stille coupling and phenol‐directed hydrogenation united the two monomeric fragments to afford 16′‐epi‐leucophyllidine in 21 steps from commercial material.