Asymmetric Reductive Amination/Ring-Closing Cascade: Direct Synthesis of Enantioenriched Biaryl-Bridged NH Lactams.

We report here a Ru-catalyzed enantioselective synthesis of biaryl-bridged NH lactams through asymmetric reductive amination and a spontaneous ring-closing cascade from keto esters and NHOAc with H as reductant. The reaction features broad substrate generality and high enantioselectivities (up to >99% ee). To showcase the practical utility, a highly enantioselective synthesis of 5-ethylindolobenzazepinone , a promising antimitotic agent, has been rapidly completed. Furthermore, the amide group in the products enables versatile elaborations through directed C-H functionalization.