Silver- versus gold-catalyzed sequential oxidative cyclization of unprotected 2-alkynylanilines with oxone.

Unprecedented domino oxidative cyclization reactions of unprotected 2-alkynylanilines to give functionalized 4H-benzo[d][1,3]oxazin-4-one or benzisoxazole derivatives in moderate to good yields are achieved by silver vs. gold selective catalysis. The search for the optimal reaction conditions revealed the divergent catalytic activity of NaAuCl4·H2O and AgNO3.