Acetylene and Substituted Acetylenes in the Presence of Alcohols

Conjugated unsaturated carboxylic acid esters can be obtained by hydro-carboxylation of acetylenes in the presence of alcohols. 

However, the reaction does not take the assumed course according to equation (1) 

The first step of the reaction relates to the hydrocarboxylation and the second step to the esterification of the primary acid formed with the alcohol present in the reaction mixture. 

As could be proved, carbonylation failed in absolute anhydrous medium under the usual reaction conditions [146, 367]. Reaction proceeds only at high temperatures after formation of water originating from the reaction of the alcohol towards ethers [146, 367]. 

When water is charged to the reactants in small quantities, the reaction rate only depends on the esterification [146]. 

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