A fast route for the synthesis of tetrazolyl oximes by a novel multicomponent reaction between Z-chlorooximes, isocyanides and trimethylsilyl azide

A library of twenty variously decorated 1,5-disubstituted-(1. H-tetrazol-5-yl)methanone oximes was prepared in one single synthetic step exploiting the combination of (Z)-chlorooximes, isocyanides and trimethylsilyl azide. The formal [3+1] cycloaddition between isocyanides and nitrile N-oxides with respect to the [3+1] cycloaddition between isocyanides and azides prevails, while the direct attack of azide onto nitrile N-oxides remains competitive. Finally, an intramolecular cyclization of a (1. H-tetrazol-5-yl)methanone oxime to a benzoisoxazole tetrazole is reported for the first time.