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.