1, 3-Dipolar cycloaddition of nitrile oxides to 4-aryl-2-alkylthio-1-azetines gave a series of oxadiazabicyclo [3.2. 0] heptenes as single diastereoisomers. Heating these cycloadducts in toluene resulted in an overall [2+ 2]-cycloreversion to give 5-alkylthio-3-aryl-1, 2, 4- oxadiazoles. In this process, the 1-azetine behaves as a thiocyanate equivalent. When the nitrile oxide substituent was 2-azidobenzene, the azide could be converted into a 1, 2, 3- ...
