Stereodivergent synthesis of the 2,3,5,6-tetrasubstituted piperidine ring system: an application to the synthesis of alkaloids and from poison frogs

Stereodivergent synthesis of the 2,3,5,6-tetrasubstituted piperidine ring system has been achieved by sequential stereocontrolled Michael-type conjugate addition reaction of appropriate enaminoesters. This methodology has been applied to the total syntheses of the poison frog alkaloids and . The relative stereochemistry of natural at the 6-position was revised, and the absolute stereochemistry of natural was determined by the present synthesis.