Markovnikov-selective hydroamination of aliphatic alkenes with anilines and azoles through light-driven multiple catalysis

Abstract Conventional acid catalysis for the Markovnikov-selective hydroamination of alkenes using anilines has limitations regarding substrate scope and low regioselectivity attributed to the buffering effect of anilines and competing Friedel–Crafts alkylation, respectively. Herein, we demonstrate the Markovnikov hydroamination of aliphatic alkenes using anilines through light-driven triple catalysis consisting of cobalt, photoredox, and weak Brønsted acid catalysts under blue light-emitting diode (LED) irradiation. Our protocol enables the generation of an alkyl cobalt(IV) species from aliphatic alkenes under weak acidic conditions, expanding the accessible N-alkylanilines and N,N-dialkylanilines. As the alkyl cobalt(IV) species reacts with anilines in an SN2 manner, unlike free carbocation, Friedel–Crafts alkylation is completely suppressed. When a Brønsted acid catalyst is replaced with Lewis base/acid pair catalysts, the quadruple catalytic system is amenable to the N-alkylation of azoles.