Proximity-assisted cycloaddition reactions of ω-azido cyanohydrin ethers: Synthesis of diversely functionalized bicyclic tetrazoles

Aliphatic azidonitriles separated by three or four carbon atoms undergo facile cyclo additions in the presence of BF 3 OEt 2 at room temperature or lower, to give bicyclic tetrazoles. 1-Azido-(2-aryl-1,3-dioxolanyl)-glycerols afford oxabicyclic tetrazoles with trimethylsilyl cyanide (TMSCN). Aspects of these facile proximity-induced 1,3-dipolar cyclo additions are discussed with mechanistic interpretations.