A number of 3, 4-disubstituted isocoumarins and polysubstituted α-pyrones have been prepared in good yields by treating halogen-or triflate-containing aromatic and α, β- unsaturated esters, respectively, with internal alkynes in the presence of a palladium catalyst. Synthetically, the methodology provides an especially simple and convenient, regioselective route to isocoumarins and α-pyrones containing aryl, silyl, ester, tert-alkyl, ...
