ChemInform Abstract: Highly Enantioselective Construction of Trifluoromethylated All‐Carbon Quaternary Stereocenters via Nickel‐Catalyzed Friedel—Crafts Alkylation Reaction.

Abstract

A highly enantioselective Friedel–Crafts alkylation reaction of indoles with β-CF3-β-disubstituted nitroalkenes was achieved using a Ni(ClO4)2–bisoxazoline complex as a catalyst, which afforded indole-bearing chiral compounds with trifluoromethylated all-carbon quaternary stereocenters in good yields with excellent enantioselectivities (up to 97% ee). The transformation of one of the products into first a trifluoromethylated tryptamine and then a trifluoromethylated tetrahydro-β-carboline by sequential nitro reduction and Pictet–Spengler cyclization were realized with complete preservation of enantiopurity.