Enantioselective Arylation of Benzylic C−H Bonds by Copper‐Catalyzed Radical Relay

A novel enantioselective copper‐catalyzed arylation of benzylic C−H bonds, using alkylarenes as a limiting reagent, has been developed. A chiral bisoxazoline ligand bearing an acetate ester moiety plays a key role in both the reactivity and enantioselectivity of the reaction. The reaction provides efficient access to various chiral 1,1‐diarylalkanes in good yields with good to excellent enantioselectivities, and displays excellent functional‐group tolerance. To the limit: An asymmetric copper‐catalyzed arylation of benzylic C−H bonds, using alkylarenes as a limiting reagent, provides efficient access to various chiral 1,1‐diarylalkanes in good yields with good to excellent enantioselectivities, and displays excellent functional‐group tolerance. The acetate ester moiety in the chiral bisoxazoline ligand accelerates the reaction, enhances the chemoselectivity, and increases the enantioselectivity of the reaction.