Easy Access to Fully Functionalized Chiral Tetrahydro-β-Carboline Alkaloids

A four-step synthetic route to fully substituted chiral tetrahydro-β-carbolines (THBCs) is described. Starting from the (R,S,S)-Friedel−Crafts/Henry adduct obtained from three-component coupling of an indole, nitroalkene, and aldehyde catalyzed by imidazoline-aminophenol−CuOTf, the (1S,3S,4R)-THBCs were readily synthesized in a three-step operation including reduction of the nitro-functionality and Pictet−Spengler cyclization.