Formation of a Delocalized Iridium Benzylidene with Azaquinone Methide Character via Alkoxycarbene Cleavage

Lewis base directed α,α-dehydrogenation of 2-(methoxymethyl)­aniline gives a cationic iridium­(III) alkoxycarbene. This alkoxycarbene is found to be subject to pyridine-promoted C–O bond cleavage in the formation of a delocalized iridium benzylidene. X-ray diffraction and DFT calculations support a structural distortion away from a classic benzylidene structure stemming from azaquinone methide character. Treatment of the iridium azaquinone methide with ethylene results in formal ethylene insertion into the vinylic C–H bond, demonstrating an unusual mechanism for net C–C bond formation via benzylic C–O cleavage.