Direct construction of 5-methyl-2-phenylisoxazol-3(2H)-ones via hypervalent iodine mediated sequential tandem oxidative cyclization of 3-oxo-N-phenylbutanamides catalyzed by zinc oxide (ZnO).

A sequential oxidative tandem cyclization reaction mediated by a combination of (diacetoxyiodo)benzene (DIB) with zinc oxide (ZnO) is presented for the synthesis of 5-methyl-2-phenylisoxazol-3(2H)-ones from β-ketobutylanilides. A variety of β-ketobutylanilide compounds were used in this approach, and a wide range of functionalized 5-methylisoxazol-3(2H)-ones were obtained in good to excellent yields.