Gold catalysis: benzanellation versus alkylidenecyclopentenone synthesis

A series of different furan-yn-ols were prepared by a three-step sequence. Their reaction with Gagoszʹs catalyst Ph3PAuNTf2 depends strongly on the substitution pattern of the substrate and the quality of the leaving group. Benzofurans, alkylidenecyclopentenones or Meyer–Schuster type products can be obtained. Improving the leaving group quality leads to the preferred formation of benzofurans.