Electrochemical one-pot synthesis of five-membered azaheterocycles: Via [4 + 1] cyclization

Various five-membered N-heterocycles, such as oxadiazoles, thiadiazoles, oxazolines and imidazoles, were prepared in one pot via electrochemical oxidation/[4 + 1] cyclization/dehydrogenative aromatization under external-oxidant-free and metal-free conditions. It is noteworthy that alcohols and electron-rich toluenes can be used as C1 synthons for the [4 + 1] cyclization together with hydrazides, N,N-dimethylhydrazinecarbothioamide, N-methylethanediamine and phenylglycinol as the four-atom fragments.