C-C bond cleavage in hydrocarbons by iridium complexes

A variety of transformations involving C-C bond cleavage in iridium complexes is described. 1,1-Dimethylcyclopentane reacts with (IrH/sub 2/(Me/sub 2/CO)/sub 2/L/sub 2/)SbF/sub 6/ (L = (p-FC/sub 6/H/sub 4/)/sub 3/P, 1) to give first ((5,5-C/sub 5/H/sub 4/Me/sub 2/)IrL/sub 2/)SbF/sub 6/ (2) and then ((MeC/sub 5/H/sub 4/)IrMeL/sub 2/)SbF/sub 6/ (3). The corresponding 5,5-dimethylcyclopentadiene gives 1,2- and 1,3-diethylcyclopentadienyl complexes by a route that involves alkyl migration from ring to metal and back. 4,4-Dimethylcyclopentene also reacts to give 3 but the 3,3-isomer follows a different path to give ((MeC/sub 5/H/sub 4/)IrHL/sub 2/)SbF/sub 6/. Crystal structures of two diene complexes of type 2 are reported and mechanisms for the reactions observed are proposed.