Enantioselective Synthesis of 2‑Amino-1,1-diarylalkanes Bearing a Carbocyclic Ring Substituted Indole through Asymmetric Catalytic Reaction of Hydroxyindoles with Nitroalkenes

An asymmetric catalytic reaction of hydroxyindoles with nitroalkenes leading to the Friedel–Crafts alkylation in the carbocyclic ring of indole is presented. The method is based on the activating/directing effects of the hydroxy group situated in the carbocyclic ring of the indole providing nitroalkylated indoles functionalizated at the C-4, C-5, and C-7 positions with high yield, regio-, and enantioselectivity. The optically enriched nitroalkanes were transformed efficiently in optically enriched 2-amino-1,1-diarylalkanes bearing a carbocyclic ring substituted indole.