Synthesis of 3-Substituted 2,1-Benzisoxazoles by the Oxidative Cyclization of 2-Aminoacylbenzenes with Oxone

An efficient approach to the synthesis of 2,1-benzisoxazoles through direct construction of the N–O bond by the chemoselective oxidation of 2-aminoacylbenzenes with Oxone is described. This alternative methodology is characterized by its simple and transition-metal-free conditions and good functional group compatibility utilizing Oxone as a green oxidant instead of hypervalent iodine compounds. Moreover, this new procedure simplifies the number of steps compared to the previously reported procedure by circumventing the use of 2-azido-substituted aryl ketones.