Gold-Catalyzed Access to Isophosphinoline 2-Oxides

Abstract

Gold(I)-catalyzed reactions of electron-poor alkynes are still a challenging process. A straightforward synthesis of phosphorus-based heterocycles, namely, 2-phenyl 1<i>H</i>-isophosphinoline 2-oxides <b>1</b>, is reported. The reaction used PPh₃AuCl precatalyst in combination with triflic acid under microwave activation and afforded isophosphinoline 2-oxides <b>1</b> in moderate to quantitative yields through a fully regioselective 6-endo-dig hydroarylation cyclization, paving the way toward an effective synthesis of phosphorus heterocycles.