Asymmetric Total Syntheses of (−)-Angustureine and (−)-Cuspareine via Rhodium-Catalyzed Hydroamination

Abstract

Concise syntheses of the Hancock alkaloids (-)-angustureine and (-)-cuspareine are presented, applying and refining a recently developed rhodium-catalyzed hydroamination for the stereoselective construction of the chiral secondary amine. Furthermore, the syntheses include an allene synthesis via boron-magnesium exchange as well as the construction of the tetrahydroquinoline motive via a hydroboration/Suzuki-Miyaura coupling sequence.