Mild and Selective Cobalt‐Catalyzed Chemodivergent Transfer Hydrogenation of Nitriles

Abstract

Herein, we describe a selective cobalt-catalyzed chemodivergent transfer hydrogenation of nitriles to synthesize primary, secondary, and tertiary amines. The solvent effect plays a key role for the selectivity control. The general applicability of this procedure was highlighted by the synthesis of more than 70 amine products bearing various functional groups in high chemoselectivity. Moreover, this mild system achieved >2000 TONs (turnover numbers) for the transfer hydrogenation of nitriles.

Cobalt–Pincer Complexes in Catalysis

“…A novel approach for the cobalt‐catalysed chemodivergent transfer hydrogenation of nitriles was also described by the group of Liu . In the presence of Co–NNP‐pincer complexes 23 and 25 and again using ammonia borane as hydrogen donor, nitriles could be reduced to primary or secondary amines depending on the applied solvent (Scheme ).…”

Cobalt Pincer Complexes for Catalytic Reduction of Carboxylic Acid Esters

“…Cobalt compounds, and here especially cobalt pincer type complexes, have been developed for a number of catalytic transformations such as polymerization, bond‐forming reactions, hydrogenations, transfer hydrogenations, hydrosilylations/hydroborations or N 2 activation . Although cobalt‐based reductions of ketones,, aldehydes , nitriles, or alkenes,,, have been studied, until now, hydrogenation of carboxylic acid esters in the presence of this metal has been scarcely examined…”

Mesoporous Metal–Metalloid Amorphous Alloys: The First Synthesis of Open 3D Mesoporous Ni‐B Amorphous Alloy Spheres via a Dual Chemical Reduction Method

“…Catalytic hydrogenation of nitriles with hydrogen and catalysts is a practical, green, and atom‐economical method for the synthesis of primary amines . However, obtaining good selectivity is challenging because nitriles are readily hydrogenated to secondary and tertiary amines . Past reports show that homogeneous catalysts are most successful in obtaining high selectivity for primary amines, but applications of conventional homogenous catalysts are limited by the difficulty to collect/recover them after the reaction.…”