Iridium-Catalyzed Enantioselective C( <i>sp</i> ³ )–H Borylation of Bicyclo[1.1.0]butanes

Bicyclo[1.1.0]butanes (BCBs) have attracted considerable interest in organic synthesis due to their versatile reactivity. However, the asymmetric synthesis of these strained systems remains a formidable challenge. We herein report an iridium-catalyzed enantioselective C( sp 3 )–H borylation of BCBs, providing access to a range of optically active borylated BCBs with high enantioselectivities. We also demonstrated synthetic applications by downstream transformations, particularly in the stereoselective preparation of optically active multisubstituted cyclobutenes.