Rapid Construction of Structurally Diverse Quinolizidines, Indolizidines, and Their Analogues via Ruthenium‐Catalyzed Asymmetric Cascade Hydrogenation/Reductive Amination

Abstract

Abstract A rapid construction of enantioenriched benzo‐fused quinolizidines, indolizidines, and their analogues by ruthenium‐catalyzed asymmetric cascade hydrogenation/reductive amination of quinolinyl‐ and quinoxalinyl‐containing ketones has been developed. This reaction proceeds under mild reaction conditions, affording chiral benzo‐fused aliphatic N ‐heterocyclic compounds with structural diversity in good yields (up to 95 %) with excellent diastereoselectivity (up to >20:1 dr) and enantioselectivity (up to >99 % ee ). Furthermore, this catalytic protocol is applicable to the formal synthesis of (+)‐gephyrotoxin.