The complex [Ru(o-CHPPh)(H)(CO)(PPh)] catalyzes the Murai reaction at room temperature. For [Ru(H)(H)(PR)], the active complex is [Ru(H)(PR)].
After the active form of the ruthenium catalyst complex is generated from 1, acetophenone coordinates to the complex via its carbonyl oxygen and agostically via its ortho C-H bond (2). As in the Ru proposed mechanism, this agostic interaction leads to the oxidative addition of the ortho C-H. Reductive elimination releases H, which remains coordinated, giving complex 3. Coordination of ethylene and decoordination of the ketone results in complex 4 which then undergoes migratory insertion of ethylene into the hydride to give 5. Following oxidative addition of H (6), the complex reductively eliminates the product to give the product agostically bound to the complex. Coordination of another acetophenone molecule regenerates complex 2.