Transition-Metal Free Amination and Hydrodefluorination of Aryl Fluorides Promoted by Solvated Electrons

Abstract

Cross-coupling reactions for constructing C−N bonds represent a pivotal advancement in chemical science. Traditional methodologies, including nucleophilic aromatic substitution (SNAr) and transition metal-catalyzed cross-couplings, have limitations concerning aryl scope, reliance on toxic and costly transition-metal catalysts, and issues related to atom economy and waste generation from ligands and additives. In this work, we introduce a novel method for aminating neutral, electron-rich, and electron-deficient aryl halides, eliminating the need for transition metals. Our approach involves the activation of aryl halides using solvated electrons generated from granulated lithium and sonication. This serves as a sustainable source of reducing power, facilitating the efficient formation of C−N bonds under near ambient conditions. Competitive selectivity studies between halide and ester functionalities were explored. Reaction scope and conducted mechanistic studies which supported the proposed radical-nucleophilic substitution (SRN₁) mechanism for the reaction. Notably, the developed reaction has a highly competitive reductive dehalogenation pathway during the C−N coupling reaction, and this mechanistic divergency was thoroughly explored. This work not only broadens the scope of C−N coupling reactions which typically employs aryl bromides and iodides and rarely aryl fluorides which is also equally abundant, but also introduces a new way to do C−N coupling reactions using solvated electrons.