1,3-Dipolar Cycloadditions of 2-Ethoxy- and 2-(Ethylthio)-1-azetines with Nitrile Oxides, Nitrile Ylides and Nitrilimines: An Unexpected 1,2,4-Triazole Formation.

Article abstract of DOI:10.1016/S0040-4020(01)85755-0

2-Ethoxy- and 2-(ethylthio)-1-azetines readily undergo 1,3-dipolar cycloadditions with nitrile oxides and nitrile ylides to give stable 4,5-bicyclic cycloadducts.With nitrilimines, however, the expected 1,3-dipolar cycloadducts and/or unexpected ring-open