Direct Carboxylation of Phenylacetylene with Carbon Dioxide. Do We Need Coin Metals?

Direct carboxylation of terminal alkynes with C–H bond functionalization combined with the use of CO2 is an efficient method for obtaining carboxylic acids. Direct carboxylation of phenylacetylene with carbon dioxide can proceed with high conversion of the substrate and selectivity of formation of the desired phenylpropiolic acid under the action of cesium carbonate and in the absence of heterogeneous catalysts regardless of the CO2 pressure. The introduction of cesium carbonate in zeolite NaX makes it possible to obtain a recyclable system for carboxylation of phenylacetylene.