Copper(0)-catalyzed aerobic oxidative synthesis of imines from amines under solvent-free conditions

Abstract

A copper(0)-catalyzed direct synthesis of imines from amines under solvent-free aerobic conditions is described. The method is applicable for the synthesis of various imines from corresponding amines such as benzylic, aliphatic, cyclic secondary and heteroaromatic amines. Being solvent free, using air as a benign oxidant, and the easy separation and easy availability of the catalyst (copper powder) are the vital advantages of present protocol.

Carbocatalysis in Liquid‐Phase Reactions

“…88 % yield of imine could be obtained over copper powder catalyst (0.3 wt % loading) at 90 °C for 20 h in open‐air conditions …”

“…The oxidative coupling of amines is a facile route to produce imines. The process is usually catalyzed by metal‐based catalysts . An 88 % yield of imines could be obtained over a copper powder catalyst (0.3 wt % loading) at 90 °C after 20 h in air (Table ).…”

Selective hydrogenation of nitriles to imines over a multifunctional heterogeneous Pt catalyst

“…Imines and their derivatives are versatile synthetic intermediates that have been extensively utilized for synthesis of dyes, fragrances, fungicides, pharmaceuticals, and agricultural chemicals . In general, there are presently three commonly utilized approaches for imines synthesis, that is, condensation of amines with ketones or aldehydes (Figure , path A), oxidative self‐coupling of amines (path B), and oxidative coupling of amines with alcohols (path C) . From a practical point of view, the use of amines as raw materials would significantly limit the widespread application of these methods because amines are normally expensive .…”

Carbokatalyse in Flüssigphasenreaktionen

“…Die oxidative Kupplung von Aminen zu Iminen ist eine einfache Route zu Iminen und wird üblicherweise mit metallbasierten Katalysatoren katalysiert . Eine Aminausbeute von 88 % konnte mit einem Kupfer‐Pulverkatalysator erreicht werden (Tabelle ).…”