The Cobalt Carbonyl-catalyzed Intramolecular Hydroesterification of Allyl Alcohol with Carbon Monoxide

Abstract

Abstract The intramolecular hydroesterification of allyl alcohol with carbon monoxide to give γ-butyrolactone occurred in the presence of cobalt carbonyl under the pressure of carbon monoxide containing a small amount of hydrogen; propionaldehyde and isobutyraldehyde were produced as by-products. The selectivity toward γ-butyrolactone increased with the use of acetonitrile or its derivatives as the solvent. The addition of pyridine, in the absence of these solvents, was effective only in increasing the reaction rate, not in increasing the selectivity toward γ-butyrolactone. On the other hand, in the presence of acetonitrile as a solvent, the selectivity toward γ-butyrolactone increased together with the reaction rate when a catalytic amount of an organic base such as pyridine was added. The higher the reaction temperature, the higher the pressure necessary to attain a maximum selectivity toward γ-butyrolactone; the best yield of γ-butyrolactone was ca. 60%. The effect of the partial pressures of hydrogen and carbon monoxide on the initial rate of the formation of each product was made clear. The experimental results were explained by a mechanism involving two different paths for the formation of an alkylcobalt carbonyl-intermediate. The order of effectiveness of acetonitrile and its derivatives as solvents has been interpreted in terms of the HSAB principle by Pearson et al.