Ligand-Controlled Regio- and Stereoselective Addition of Carboxylic Acids Onto Terminal Alkynes Catalyzed by Carbonylruthenium(0) Complexes

The addition of carboxylic acids onto terminal alkynes was catalyzed by mononuclear ruthenium(0) complexes to give enol esters in high yields. By using ligands with different electronic properties, product selectivity was achieved. E-enol esters were preferentially produced when tricarbonyl(eta(4)-diene)ruthenium complexes were used; while geminal enol esters were produced when tricarbonylbis(phosphane)-ruthenium complexes were used.