Improved method for the synthesis of 1-vinylindole

A highly efficient method has been developed for the synthesis of 1-vinylindole based on the vinylation of indole by acetylene at atmospheric pressure using the superbase KOH-DMSO catalytic system. The method allows the preparation of the 1-vinylindole in 94% yield with a purity of 99% (after a single distillation of the crude product).