Concise synthesis of optically active ring-A substituted tryptophans

Article abstract of DOI:10.1016/S0040-4039(98)02497-6

A concise synthesis of optically active tryptophan derivatives was developed via diastereoselective alkylation of the Schollkopf chiral auxiliary 4 to provide alkyne 2 which underwent palladium-catalyzed heteroannulation with iodoanilines 1 to furnish protected tryptophans 3. Hydrolysis and subsequent saponification of 3 provided the desired tryptophans 12 in good yields.