Transition-metal free boron triiodide-mediated reduction of nitroarenes from simple borohydride reagents

The reduction of nitroarenes using KBH4 and I2 is described. KBH4 and I2 are used to generate BI3 in situ, which was shown to be the active reductant. Conditions were optimized for BI3 generation, and then applied to a wide range of nitroarene reductions, including traditionally challenging substrates. The method constitutes a practical nitroarene reduction which produces low toxicity byproducts boric acid and potassium iodide upon workup.