Facile Oxygen Atom Insertion into Unactivated C(sp3)-C(sp2) Single Bonds in Reactions of Iridium(III) Complexes with O2

The Ir(III) pyridylidene TpMe2tiebar above startr(CH2CH2-o-tiebar above endC6H4)(tiebar above startCN(H)CHCHCHtiebar above endCH) (3; TpMe2 = hydrotris(3,5-dimethylpyrazolyl)borate) reacts with oxygen (air), under mild conditions, to afford a bicyclic ether-semiaminal species. The new structure derives formally from two oxidative events. One is dehydrogenative in nature (loss of 2H), and the other consists of the insertion of an oxygen atom into a nonactivated benzylic C–C bond. The reaction has been extended to a related iridacycle that contains a pyrazole coligand instead of the pyridylidene.