Ruthenium-catalyzed synthesis of β-oxo esters in aqueous medium: Scope and limitations

Abstract

The ability of the hydrosoluble ruthenium(II) complexes [RuCl₂(η⁶-arene)(PTA)] 3a–d, [RuCl₂(η⁶-arene)(PTA-Bn)] 4a–d, [RuCl₂(η⁶-arene)(DAPTA)] 5a–d, [RuCl₂(η⁶-arene)(TPPMS)] 6a–d (arene = C₆H₆, p-cymene, 1,3,5-C₆H₃Me₃, C₆Me₆) to promote the atom-economic formation of β-oxo esters, by addition of carboxylic acids to terminal propargylic alcohols in water has been explored. Scope, limitations and catalyst recycling have been evaluated using the most active catalyst [RuCl₂(η⁶-C₆H₆)(TPPMS)], 6a.