Mukaiyama hydration
The Mukaiyama hydration is an organic reaction involving formal addition of an equivalent of water across an olefin by the action of catalytic bis(acetylacetonato)cobalt(II) complex, phenylsilane and atmospheric oxygen to produce an alcohol with Markovnikov selectivity. The reaction was developed by Teruaki Mukaiyama at Mitsui Petrochemical Industries, Ltd. Its discovery was based on previous work on the selective hydrations of olefins catalyzed by cobalt complexes with Schiff base ligands and porphyrin ligands. Due to its chemoselectivity (tolerant of other functional groups) and mild reactions conditions (run under air at room temperature), the Mukaiyama hydration has become a valuable tool in chemical synthesis. Mechanism In his original publication, Mukaiyama proposed that the reaction proceeded through the intermediacy of a cobalt peroxide adduct. A metal exchange reaction between a hydrosilane and the cobalt peroxide adduct leads to a silyl peroxide, which is converted to the alcohol upon reduction, presumably via action of the cobalt catalyst. Studies investigating the mechanism of cobalt-catalyzed peroxidation of alkenes by Nojima and coworkers, support the intermediacy of a metal hydride that reacts with the alkene directly to form a transient cobalt-alkyl bond. Homolysis generates a carbon centered radical that reacts directly with oxygen and is subsequently trapped