Highly Efficient Single A³-Coupling (Aldehyde-Amine-Alkyne) Reaction Catalyzed by Air Stable Silver-(N-Heterocyclic Carbene) Complexes: Synthesis and Characterization

Abstract

The interaction of N,N-disubstituted benzimidazolium salts 2a–e with Ag₂O formed new silver-(N-heterocyclic carbene) complexes 3a–e. Structural characterization of silver-(N-heterocyclic carbene) complexes was conducted by using NMR, FT-IR and elemental analysis. Preliminary catalytic studies using all the silver complexes 3a–e were performed on three-component coupling reaction of a series of aldehydes with alkynes and amines was demonstrated. Most of these reactions led to formation of the expected propargylamines in good conversions using low amounts catalyst and obviating both the use of purified reagents as employ of a glovebox. Complexes 3a and 3c exhibited good catalytic activities under neat conditions. The silver complexes 3a–e showed luminescence properties in CH₃CN at room temperature.

Keywords:

• Multicomponent reaction
• one pot reaction
• A³-coupling reaction
• propargylamines
• ketones
• amines
• alkynes
• silver complexes

Acknowledgement

The authors gratefully acknowledge Qassim University, represented by the Deanship of Scientific Research, on the financial support for this research under the number (10124-cosao-2020-1-3-I) during the academic year 1441AH/2020AD.

Disclosure statement

No potential conflict of interest was reported by the authors.