Transition metal catalyzed stereodivergent synthesis of - and -δ-vinyl-lactams: formal total synthesis of (-)-cermizine C and (-)-senepodine G.

A stereodivergent and diastereoselective transition-metal-catalyzed intramolecular hydroamidation of allenes and alkynes furnishing δ-vinyl-lactams is reported. Employing a rhodium catalyst allowed for the selective synthesis of the -δ-lactam. Conversely, a palladium catalyst led to the formation of the -δ-lactam in high selectivity. The new method shows high functional group compatibility and assorted synthetic transformations were demonstrated as well as its utility for the enantioselective formal total syntheses of (-)-cermizine C and (-)-senepodine G.