Biomimetic Construction of the Hydroquinoline Ring System. Diastereodivergent Enantioselective Synthesis of 2,5-Disubstituted cis-Decahydroquinolines

The straightforward enantioselective construction or the hydroquinoline ring system from 1.5-polycarbonyl derivatives, using (R)-phenyglycinol as a chiral latent form of ammonia, is reported. The process mimics the key steps believed to occur in nature in the biosynthesis of amphibian decahydroquinoline alkaloids. Diastereodivergent routes to enantiopure cis-2,5-disubstituted decahydroquinolines, including the alkaloid pumiliotoxin C (cis-195A), are developed.