Heck reaction of endocyclic enecarbamates with diazonium salts. Formal enantioselective syntheses of alkaloids (−)-codonopsine and (−)-codonopsinine, and the synthesis of a new C-aryl azasugar

Abstract

Formal total syntheses of the pyrrolidine alkaloids (−)-codonopsine and (−)-codonopsinine, as well as the synthesis of a new C-aryl azasugar were accomplished from a common 5-membered, enantiomerically pure endocyclic enecarbamate. The key step in those syntheses relies on a novel and practical version of the Heck reaction involving endocyclic enecarbamates and diazonium salts.