Synthesis of N-Substituted Indoles via Aqueous Ring-Closing Metathesis

We report herein the synthesis of N-substituted indoles resulting from the ring-closing metathesis of indole precursors bearing N-terminal alkenes. The aqueous metathesis of the indole precursors gave good yields of N-substituted indoles (up to 72%) with commercial metathesis catalysts and with artificial metalloenzymes based on the biotin-streptavidin technology. Strikingly, the yield of the N-acetylindole increases in presence of a second metathesis substrate.[GRAPHICS].