Silica‐Immobilized NHC–Cu^I Complex: An Efficient and Reusable Catalyst for A³‐Coupling (Aldehyde–Alkyne–Amine) under Solventless Reaction Conditions

Abstract

Abstract A novel silica‐immobilized NHC–Cu I complex was developed and used as a highly efficient catalyst in the three‐component coupling reactions of aldehydes, alkynes and amines (A 3 ‐coupling). The reactions were applicable to aromatic and aliphatic aldehydes, alkynes and amines, and generated the corresponding propargylamines in good yields only in the presence of SiO 2 –NHC–Cu I (2 mol‐%) at room temp. under solvent‐free reaction conditions. Moreover, the catalyst was quantitatively recovered from the reaction mixture by a simple filtration and reused for ten cycles with almost consistent activity.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)