Enantioselective syntheses of 2,5-disubstituted pyrrolidines based on iridium-catalyzed allylic aminations--total syntheses of alkaloids from amphibian skins

A broadly applicable route to trans‐2,5‐disubstituted pyrrolidines has been developed. Key steps are an asymmetric iridium‐catalyzed allylic amination, a Suzuki–Miyaura coupling, and an intramolecular aza‐Michael addition. Enantiomeric excesses in the range of 93–99 % ee have been achieved. Total syntheses of the alkaloids (?)‐ 225 C , (+)‐ and (?)‐ 223 H (xenovenine), (+)‐ 223 AB , (+)‐ 195 B , and (+)‐ 223 R have been carried out as applications.