Titanium-Mediated Catalytic Hydrogenation of Monocyclic and Polycyclic Arenes

Two electron-reduction of the Ti(IV) guanidinate complex (ImDippN)(Xyketguan)TiCl2 gives (η6-ImDippN)(xyketguan)Ti (1intra) and (ImDippN)(Xyketguan)Ti(η6-C6H6) (1inter) (xyketguan = [(tBuC=N)C(NXylyl)2]-, Xylyl = 2,5-dimethylphenyl) in the absence or presence of benzene, respectively. These complexes have been found to hydrogenate monocyclic and polycyclic arenes under relatively mild conditions (150 psi, 80 °C) – the first example of catalytic, homogeneous arene hydrogenation with TON > 1 by a Group IV system.