A general synthesis of nitriles from nitroalkanes with bis(catecholato)diboron

Abstract

A metal-free method for accessing nitriles from nitroalkanes is reported. The reaction is mediated by 1,8-diazabicyclo[5.4.0]undec-7-ene with bis(catecholato)diboron as the deoxygenation reagent. Both boron units are engaged, therefore only requiring slightly more than stoichiometric amounts of the diboron reagent. A broad range of nitroalkanes can be converted into the corresponding nitriles, including structural complex molecules. No erosion of enantiopurity is seen with a β-chiral nitroalkane to arrive at an α-chiral nitrile. The value of the new method is demonstrated by a short synthesis of 2-arylpropionic acids (profens) to potentially replace the Boots–Hoechst–Celanese route.