C(sp 3 )−H Oxidative Addition and Transfer Hydrogenation Chemistry of a Titanium(II) Synthon: Mimicry of Late‐Metal Type Reactivity

Two‐electron reduction of the Ti IV compound ( ket guan)(Im Dipp N)Ti(OTf) 2 ( 3 ) gives the arene‐masked complex ( ket guan)(η 6 ‐Im Dipp N)Ti ( 1 ) in excellent yield. Upon standing in solution, 1 converts to a Ti IV metallacycle ( 4 ) through dehydrogenation of a pendant isopropyl group. Spectroscopic evidence shows this transformation initially proceeds via the oxidative addition of a C(sp 3 )−H bond and can be reversed upon exposure of 4 to H 2 . Interestingly, treatment of 1 with cyclohexene gives cyclohexane and 4 via a titanium‐mediated transfer hydrogenation reaction, a process that can be extended to catalytically hydrogenate other unsaturated hydrocarbons under mild conditions. These results, rare for the early‐metals, suggest 1 possesses chemical characteristics reminiscent of noble, late‐metals.