Carbon–carbon bond activation by B(OMe)(3)/B(2)pin(2)-mediated fragmentation borylation

Selective carbon–carbon bond activation is important in chemical industry and fundamental organic synthesis, but remains challenging. In this study, non-polar unstrained Csp(2)–Csp(3) and Csp(2)–Csp(2) bond activation was achieved by B(OMe)(3)/B(2)pin(2)-mediated fragmentation borylation. Various indole derivatives underwent C2-regioselective C–C bond activation to afford two C–B bonds under transition-metal-free conditions. Preliminary mechanistic investigations suggested that C–B bond formation and C–C bond cleavage probably occurred in a concerted process. This new reaction mode will stimulate the development of reactions based on inert C–C bond activation.