reactions of n-isocyaniminotriphenylphosphorane with cyclopentanone have been studied in the presence of aromatic carboxylic acids and primary amines, proceeds smoothly at room temperature under neutral conditions to afford sterically congested 1,3,4-oxadiazole derivatives by an intramolecular aza-wittig cyclization in ch2cl2 in excellent yields. the structures of the products were deduced from...
