Metal-Free Multicomponent Reaction for Synthesis of 4,5-Disubstituted 1,2,3-(NH)-Triazoles

A metal-free domino reaction was developed for efficient synthesis of 4,5-disubstituted 1,2,3-(NH)-triazoles by sequentially coupling sulfur salts with aldehydes and sodium azide. In the presence of L-proline, olefinic sulfur salt intermediates rather than epoxides are formed insitu via the coupling of sulfur salts with aldehydes and cyclize with azide ion. This process features mild conditions, high efficiency, commercially available starting materials, and wide substrate scope.