Design and Synthetic Utility of New HAT Organocatalysts Derived from Commercially Available Diamines

A series of hydrogen-atom transfer (HAT) organocatalysts were conveniently prepared from commercially available diamine compounds, and their utility in photoinduced HAT catalysis ability was investigated. The combination of these readily available HAT organocatalysts with the Fukuzumi photoredox catalyst enables efficient and site-selective C−H alkylation of various functionalized substrates ranging from simple hydrocarbons to complex molecules. The site-selective C–H alkylation of multifunctional molecules has also been demonstrated. Notably, the sequential one-pot photoinduced dialkylations of bifunctional substrates can be realized. Mechanistic studies suggested that the 1-naphthylmethyl moiety on one nitrogen atom of the diamine compounds plays a crucial role in the reaction by inducing the facile generation of a cationic aminium radical on the other nitrogen of the diamine as an active intermediate for the HAT process.