One-Pot, Four-Component Synthesis of Fully Substituted 1,3,4-Oxadiazole Derivatives from (Isocyanoimino)triphenylphosphorane, a Primary Amine, an Aromatic Carboxylic Acid, and Chloroacetone
presence of an aromatic carboxylicacid 3 and leads to the formation of the corresponding iminophosphorane intermediate 9 (Scheme 2). The 1,3,4‐oxadiazole derivatives 5 are then formed via an intramolecular aza‐Wittig reaction of the iminophosphorane intermediate 9. The reactions were completed under neutral conditions at room temperature. The fully substituted 1,3,4‐oxadiazole derivatives 5 were produced