Development of Novel Methodology in Organic Synthesis Using Cobalt (II) Catalyst

Our recent study on oxygenation and carbon-carbon bond forming reaction of olefinic compounds using a series of cobalt (II) catalysts have been descrived in the following four reactions. (1) Catalytic hydration of olefins with molecular oxygen and 2-propanol is performed by using bis (1, 3-diketonato) cobalt complex (Oxidation-Reduction Hydration). (2) The above cobalt (II) complex efficiently promoted the novel peroxygenation of a wide range of olefinic compounds with molecular oxygen and triethylsilane to afford the triethylsilyl peroxides in high yields. (Triethylsilylperoxygenation) (3) The cross coupling reactions of α, β-unsaturated compound with aldehyde and phenylsilane proceed in the presence of the cobalt (II) catalyst to give the aldol-type product. (4) Under the similar condition, catalytic oximation of α, β-unsaturated compound is achieved by using butylnitrite as an electrophile. The synthetic applications and a possible reaction path-way are also described.