Selective Cleavage of the C−C Bonds of Aminoethyl Groups, via a Multistep Pathway, by a Pincer Iridium Complex

A pincer-ligated iridium complex is found to react with N-ethylamines, HN(Et)R (R = cyclohexyl, tert-butyl, ethyl), to give the corresponding iridium isocyanide complexes (PCP)Ir(CH3)(H)(CNR) (PCP = κ3-2,6-(tBu2PCH2)2C6H3). This novel, regioselective C−C bond cleavage reaction occurs readily under mild conditions (25−45 °C). The reaction is shown to proceed via initial dehydrogenation of the amine to give the corresponding imine (N-ethylidenealkylamine). The ethylidene sp2 C−H bond then undergoes addition to iridium, followed by methyl migration.