Conjugated ynones, in particular α,β-acetylenic ketones, are of great interest due to their wide range of applications in natural products and in organic synthesis. They are versatile intermediates for the preparation of heterocyclic derivatives such as pyrroles, furans, pyrazoles, isoxazoles and others.

Recently, the catalytic coupling of acyl chlorides and terminal alkynes to give ynones, known as the acyl Sonogashira reaction, has received considerable attention. Typically, this transformation is conducted under conventional conditions for the Sonogashira coupling involving Pd(PPh₃)₂Cl₂, CuI, and TEA. Nevertheless, heterogeneous palladium or copper catalysts have also demonstrated to be efficient in this coupling reaction. In particular, there has been a great interest in using metallic nanoparticles as catalysts due to their high activity and selectivity, and the possibility to recover and reuse the catalyst. In this sense, our research group possesses extensive experience in the preparation of metallic nanocatalysts and their application in various chemical transformations, including cycloaddition reactions, C-C and C-Het. bond forming reactions, reduction and oxidation of different functionalities, among others.

In this work, we want to present our findings on the acyl-Sonogashira coupling catalyzed by copper (monometallic) or copper-palladium (bimetallic, 4:1 molar ratio) nanoparticles (NPs) immobilized in various inorganic materials. We found that the reaction must be conducted at 80°C when using CuNPs, whereas Cu-PdNPs demonstrates exceptional efficiency in promoting the reaction at room temperature. Both catalysts can be reused without any pre-treatment after separation from the reaction medium and subsequent washing.