Anionic Group 6 Hydrides and Carboxylates as Homogeneous Catalysts for Reduction of Aldehydes and Ketones

Article abstract of DOI:10.1021/ja00278a016

The catalytic reduction of aldehydes and ketones to alcohols has been successfully effected through the use of M(CO)5B^- (M=Cr, W, Mo; B=Broensted base) under hydrogen pressure in THF or MeOH.Both organic (CH3CO2^-) and inorganic -> Broensted bases have been utilized for these reactions.Mechanistic models of this process include the ligand-assisted heterolytic cleavage of H2, an alkoxide-stabilized oxidative-addition dihydride, or an η²-H2 group 6 metal carbonyl as intermediates which are expected to produce a highly reactive group 6 anionic hydride.Subsequent steps involve hydride attack on the carbonyl carbon followed by protonation to produce the alcohol.