Applying Na/Co() bimetallic partnerships to promote multiple Co-H exchanges in polyfluoroarenes

Heterobimetallic base NaCo(HMDS) 3 [HMDS = N(SiMe 3 ) 2 ] enables regioselective di-cobaltation of activated polyfluoroarenes under mild reaction conditions. For 1,3,5-C 6 H 2 X 3 (X= Cl, F), NaCo(HMDS) 3 in excess at 80 °C impressively induces the collective cleavage of five bonds (two C-H and three C-X) of the substrates via a cascade activation process that cannot be replicated by LiCo(HMDS) 3 or KCo(HMDS) 3 . Using a bimetallic base combining Na and Co( ii ) enables the regioselective sodium-mediated di-cobaltation of fluoroarenes as well as transforming the three C-F bonds of trifluorobenzene into C-N bonds via a cascade activation process.