B(C6F5)3-Catalyzed redox-neutral β-alkylation of tertiary amines using p-quinone methides via borrowing hydrogen.

Herein, we present the first example of catalytic redox-neutral β-functionalization of tertiary amines through a borrowing hydrogen process. This B(C6F5)3-catalyzed procedure utilizes commercially or readily available catalysts and substrates and promotes a direct functionalization of the C(sp3)-H bond at the β-position of acyclic tertiary amines through conjugate addition to para-quinone methides. Compared to previous work on direct β-functionalization of tertiary amines under oxidative conditions, besides being metal-free, the significant advantage of this method is that neither stoichiometric oxidants nor reductants are needed which may otherwise generate unnecessary waste.