Expedient Pd‐Catalyzed α‐Arylation towards Dibenzoxepinones. Pivotal Manske's Ketone for the Formal Synthesis of Cularine Alkaloids

Abstract

The general synthesis of diversely substituted dibenzoxepinones by a combined Pd‐catalyzed α‐arylation and SNAr strategy is reported and applied to the synthesis of Manske's ketone, a key intermediate en route to the total synthesis of cularine alkaloids. In the course of this work, an unanticipated ring contraction reaction to a xanthone was observed and serves as a caveat for the conditions of the widely used α‐arylation reaction.