Borane-Catalyzed Chemoselectivity-Controllable N-Alkylation And Ortho C-Alkylation Of Unprotected Arylamines Using Benzylic Alcohols

An unprecedented protocol for the efficient and highly chemoselective alkylation of unprotected arylamines using alcohols catalyzed by B(C6F5)(3) has been developed. The reaction gives N-alkylated products and ortho C-alkylated products in different solvents in good chemoselectivities and yields. Control experiments and DFT calculations indicated that the borane underwent alcohol/arylamine exchange to ensure catalytic activity, and a possible mechanism involving a carbocation is proposed.