Design of Manganese Phenol Pi-complexes as Shvo-type Catalysts for Transfer Hydrogenation of Ketones

Catalytic hydrogenation is one of the most important reactions both in academic research and industry. We explored ability of the manganese pi-complexes to act as Shvo-type catalysts for transfer hydrogenation of ketones. DFT calculations suggested that the transfer of hydrogen atoms from the hypothetical intermediate [(C6Me3H2OH)Mn(CO)(2)H] to acetone has low activation barrier of 10.9 kcal mol(-1). Experimentally a number of ketones with various functional groups (OMe, NH2, Cl, CF3, pyridyl) were successfully reduced in isopropanol at 90 degrees C in the presence of the complex[(C6Me3H2OH)Mn(CO)(3)]BF4 (1 mol %) and (BuOK)-Bu-t (75 mol %). However, further investigation revealed that the reduction was mainly promoted by base rather than the manganese complex.