Palladium-catalyzed annulation of internal alkynes

Abstract

<p>A variety of aromatic and vinylic hetero- and carbocycles have been prepared in good yields by treating halogen- or triflate-containing substrates with internal alkynes in the presence of a palladium catalyst. Synthetically, the methodology provides a convenient, regioselective route to indenones, isocoumarins, [alpha]-pyrones, benzofurans, isochromenes, phenanthrenes, and other miscellaneous hetero- and carbocycles containing aryl, silyl, ester, and tert-alkyl groups. The regiochemistry of the process is generally controlled sterically and the reaction yields usually range from 50-80%.</p>