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