An Efficient Method for the Direct Peroxygenation of Various Olefinic Compounds with Molecular Oxygen and Triethylsilane Catalyzed by a Cobalt(II) Complex

Article abstract of DOI:10.1246/bcsj.63.1305

An efficient method for the direct peroxygenation of various olefinic compounds with molecular oxygen and triethylsilane (Et3SiH) was developed by the use of a catalytic amount of a bis(1,3-diketonato)cobalt(II) complex.According to the above method, 1-phenyl-3-triethylsilyldioxybutane (2) was directly produced from 4-phenyl-1-butene (1) by means of a reaction with O2 and Et3SiH at room temperature.Styrene (3) and ethyl acrylate (5a) were also smoothly peroxygenated to give 1-phenyl-1-triethylsilyldioxyethane (4) and ethyl 2-triethylsilyldioxypropionate (6a) by using a small amount of t-BuOOH as an initiator.The successive desilylation of 6a and reduction of the resulting ethyl 2-hydroperoxypropionate (8a) afforded the corresponding alcohol, ethyl lactate (10a), in a high yield.The synthetic utility of the present peroxygenation reaction was demonstrated in the preparation of α-hydroxy esters 10a-e from several α,β-unsaturated esters 5a-e via the corresponding triethylsilyldioxy derivatives.