Synthesis of nitriles via ruthenium catalyzed dehydrogenation of primary amines: A combined experimental and theoretical study

Abstract

Nitriles represent one of the most important classes of organic compounds used as intermediates in the synthesis of biologically active compounds and pharmaceutical substances. Nitriles are also versatile intermediates in synthetic organic chemistry due to their easy conversion into amines, amides, carboxylic acids, aldehydes and esters. Traditional methods for the preparation of nitriles often require hazardous reagents, severe reaction conditions and/or have limited selectivity. Alternatively, amines can directly be oxidized to nitriles by the use of transition metal catalysis. Although developments in this field are scarce, in this communication we show that Ru-NHC (NHC = N-heterocyclic carbene) complexes lead to the formation of nitriles with the concomitant liberation of hydrogen and without the need of any additive. A plausible mechanism based on DFT calculations is proposed and supported by experimental evidences.