Carbonylation of Oxiranes in Methanol by Cobalt Carbonyl Catalysts

Abstract

Cobalt catalyzed hydroesterification of oxiranes with carbon monoxide and methanol was studied as functions of catalysts, solvents, additives, reaction temperature and CO pressure to search for the optimum conditions for β -hydroxy esters, suppressing the side reactions (isomerization, deoxygenation, addition of alcohol, and polymer formation). Under the optimum conditions, methyloxirane[1], 1, 1-dimethyloxirane[ 2 ], and phenyloxirane [ 3 ], gave methyl 3-hydroxybutyrate, methyl 3-hydroxy-3-methylbutyrate, and methyl 3-hydroxy-2-phenylpropionate [ 4 ] as main products in 76% (cf. Run 7 in Table 1), 60% (cf. Run 32 in Table 3), and 32% (cf. Run 48 in Table 5) yields, respectively. In the case of [ 3 ], methyl 2-phenylacrylate and methyl 3-hydroxy-3-phenylpropionate were obtained besides [ 4 ] with the yields of 5% and 8%, respectively. The position of the addition of ester group to oxirane ring was reasonably interpreted in terms of steric and electric effects of the substituent group.