Transition Metal-free Selenium-mediated Aryl Amines via Reduction of Nitroarenes

A scalable and operationally simple on water seleno-mediated reduction of nitroarenes to the respective aryl amines with NaBH4 is described. The reaction proceeds under transition metal-free conditions and is promoted by the formation of Na2Se, which is the effective reducing agent involved in the mechanism. This mechanistic information enabled the development of a mild NaBH4-free protocol for the selective reduction of nitro derivatives bearing labile moieties, including nitrocarbonyl compounds. The selenium-containing aqueous phase can be successfully reused up to four reduction cycles, thus further improving the efficiency of the protocol disclosed.