Photoredox-Catalyzed Radical Hydroalkylation of Azobenzenes with Alkylboronic Acids

The facile synthesis of <i>N</i>-alkyl-<i>N</i>,<i>N</i>'-diarylhydrazines has been a long-standing challenge. Here, we report a photoredox-catalyzed hydroalkylation of azobenzenes with alkylboronic acids, which successfully affords diverse <i>N</i>-alkyl-<i>N</i>,<i>N</i>'-diarylhydrazines. With an acridinium salt as the photocatalyst and upon visible light irradiation, a broad range of azobenzenes and alkylboronic acids reacted smoothly in the presence of a Lewis base at ambient temperature. Mechanistic studies revealed that the reaction proceeds via the generation of alkyl radicals and is facilitated by photoredox catalysis.