The Substituents Effect on the Oxymethylation of Carbon-Carbon Double Bond in the Presence of Iron Carbonyl Catalyst

Abstract

Unsaturated esters, nitriles and alcohols bearing a terminal double bond were oxymethylated with CO and H₂O at 170°C in the presence of iron carbonyl-amine catalyst, and the effect of the position of the substituents upon the competitive reactions at the double bond, hydrogenation and oxymethylation, was investigated. Acrylates and acrylonitrile were hydrogenated exclusively, but the formation of lactones or hydroxyesters was observed in the reactions from crotonate to 5-hexenoate. Examination of the product distribution proved that the ratio of the oxymethylated products increased in the order of the distance between the double bond and the ester group. The similar tendency was also found in the reactions of the unsaturated alcohols from allyl alcohol to 4-pentenol. In this case, the isomerization of allyl-type alcohol to aldehyde was presumed to play a principal role in the hydrogenation. Based upon some experimental evidences for its presence. in the reaction mixture, mononuclear hydridoirontetracarbonyl anion was considered to be an active species in the two reactions.