Metalloradical-Catalyzed Selective 1,2-Rh‑H Insertion into the Aliphatic Carbon–Carbon Bond of Cyclooctane

The selective aliphatic carbon–carbon
activation of cyclo-octane
(c-octane) was achieved via the RhII(ttp)-catalyzed 1,2-addition
of Rh­(ttp)H to give Rh­(ttp)­(n-octyl) (ttp = tetratolylporphyrinato
dianion) in good yield under mild reaction conditions. This mechanism
is further supported by DFT calculations. The reaction worked only
with the sterically accessible Rh­(ttp) porphyrin complex but not with
the bulky Rh­(tmp) system (tmp = tetrakismesitylporphyrinato dianion),
thus showing the highly steric sensitivity of carbon–carbon
bond activation by transition metal complexes.