Allylic and vinylic carbonylation of cyclohexene catalysed by [Ru^II(EDTA-H)(CO)]

Abstract

The complex [Ru^II(EDTA-H)(CO)] (EDTA = ethylenediaminetetraacetic acid) catalyses the carbonylation of cyclohexene in alcohol:water (80:20) mixture to give cyclohexene-1-carboxaldehyde, cyclohexene-3-carboxaldehyde and cyclohexane-carboxaldehyde. The optimum conditions of the reaction are 120°C and 20 atm CO partial pressure. The effect of catalyst, CO pressure and cyclohexene concentration on the initial rates of carbonylation was investigated. The rate of carbonylation exhibits first-order dependence with respect to catalyst, CO pressure and substrate concentration. The effect of temperature on the rate of cyclohexene carbonylation was studied and the activation energy, E_a, evaluated at 16±1 Kcal mol⁻1. Carbonylations of 1-methyl-, 3-methyl- and 4-methylcyclohexenes conducted at 160°C and 20 atm CO partial pressure gave the corresponding alcohols.