Synthesis of benzisoxazoles by the [3 + 2] cycloaddition of in situ generated nitrile oxides and arynes.

A variety of substituted benzisoxazoles has been prepared by the [3 + 2] cycloaddition of nitrile oxides and arynes. Both components, being highly reactive intermediates, have been generated in situ by fluoride anion from readily prepared aryne precursors and chlorooximes. The reaction scope is quite general, affording a novel, direct route to functionalized benzisoxazoles under mild reaction conditions.