One‐Pot Sequential Hydrogenation and Kinetic Resolution: Simultaneous Synthesis of Two Classes of Optically Active N ‐Heterocycles

Comprehensive Summary Dihydropyrrolo[1,2‐ a ]quinoxalines are important structural motifs widely present in natural products and biologically active molecules. Despite various well‐developed racemic protocols, the enantioselective synthesis of optically active dihydropyrrolo[1,2‐ a ]quinoxalines via asymmetric catalysis has been relatively less studied. In this work, a borane‐catalyzed hydrogenation of pyrrolo[1,2‐ a ]quinoxalines and a chiral phosphoric acid‐catalyzed oxidative kinetic resolution of the resulting racemic dihydropyrrolo[1,2‐ a ]quinoxalines via transfer hydrogenation have been successfully integrated into a one‐pot process. A variety of optically active dihydropyrroquinoxalines and dihydrobenzoxazinones were obtained simultaneously with high levels of yields and ee's. Notably, this sequential process provides a straightforward method for synthesizing enantioenriched dihydropyrrolo[1,2‐ a ]quinoxaline derivative, which acts as potent agricultural fungicides. The present work combines frustrated Lewis pair‐catalyzed hydrogenation and chiral phosphoric acid‐catalyzed transfer hydrogenation, providing a facile and efficient method for the simultaneous synthesis of two distinct classes of optically active nitrogen‐containing heterocycles.