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