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.