Intermolecular Reductive C-N Cross Coupling of Nitroarenes and Boronic Acids by P^III/P^V═O Catalysis

A main group-catalyzed method for the synthesis of aryl- and heteroarylamines by intermolecular C-N coupling is reported. The method employs a small-ring organophosphorus-based catalyst (1,2,2,3,4,4-hexamethylphosphetane) and a terminal hydrosilane reductant (phenylsilane) to drive reductive intermolecular coupling of nitro(hetero)arenes with boronic acids. Applications to the construction of both C_sp2-N (from arylboronic acids) and C_sp3-N bonds (from alkylboronic acids) are demonstrated; the reaction is stereospecific with respect to C_sp3-N bond formation. The method constitutes a new route from readily available building blocks to valuable nitrogen-containing products with complementarity in both scope and chemoselectivity to existing catalytic C-N coupling methods.