Construction of Chiral 1,2-Azaborines via Rhodium-Catalyzed Enantioselective Carbene N–H Bond Insertion

The development of general and efficient strategies for the synthesis of chiral 1,2-azaborines remains scarce and challenging. Here, we report a Rh-catalyzed enantioselective carbene N-H bond insertion to construct a series of chiral 1,2-azaborines in up to 96% yield with 96% ee. This protocol provides a practical approach to access chiral 1,2-azaborines through N-substituent functionalization. More importantly, the formed chiral compounds stereospecifically transform to novel B(sp³) chiral 1,2-azaborines with B, N, and C contiguous stereocenters readily.