Unexpected C−C Bond Cleavage and C−C Bond Formation Observed in the Reaction of a Cationic Iridium Complex with Heteroatom-Substituted Cyclopropanes

Abstract

Iridium complex Cp*(PMe3)Ir(CH3)OTf (1) and alkylaminocyclopropanes react via a well-understood initial C−H bond activation with a subsequent C−C bond-breaking step to yield a variety of π-allyl complexes [Cp*(PMe3)Ir(η3-C3H4NR1R2)][OTf] (R1 = R2 = Bn; R1 = Bn, R2 = Ph) and methane. However, diphenylamino, alkoxy, or siloxycyclopropanes, when treated with complex 1, yield a new π-allyl complex [Cp*(PMe3)Ir(η3-C3H4CH3)][OTf] (8) and the corresponding amine or alcohol. The methyl group initially bound to iridium is no longer extruded as methane, but instead is incorporated into the allyl moiety to give a new carbon−carbon bond. A detailed mechanistic study provides evidence in support of an initial C−C bond activation mechanism as opposed to the initial C−H bond activation observed with other known substrates.