Cycloadditions of nitrile oxides with benzofurazan N-oxides

Abstract

The reaction of benzofurazan N-oxides with nitrile oxides in refluxing dichloromethane affords the mono- and bis-adducts to the benzene ring, as well as benzo-as-triazine tri-N-oxides. The site-, regio-, and stereo-selectivity of the cycloadditions, the influence of substituents, and the isomeric composition of the isolated mono- and bis-adducts are discussed, and compared with the results of the cycloadditions to the corresponding benzofurazans.