A Solvent-Free and One-Pot Strategy for Ecocompatible Synthesis of Substituted­ Benzofurans from Various Salicylaldehydes, Secondary Amines, and Nonactivated Alkynes Catalyzed by Copper(I) Oxide Nanoparticles

Abstract

Copper(I) oxide nanoparticles (CONPs) catalyze multicomponent coupling/cycloisomerization reactions between various 2-hydroxybenzaldehydes, secondary amines, and nonactivated alkynes to give 2,3-disubstituted 1-benzofurans. All reactions are carried out under solvent-and ligand-free conditions at 100 °C in air. The combination of copper-catalyzed C-H activation and an Oannulation process is essential for this transformation. This methodology provides rapid access to substituted 1-benzofurans in good to excellent yields with high atom economy and high catalytic efficiency. This procedure eliminates the need for propargylamine derivatives, uncyclized intermediates that make purification difficult. The CONPs and tetrabutylammonium bromide were reused successfully for up to five times.

σ-H–H, σ-C–H, and σ-Si–H Bond Activation Catalyzed by Metal Nanoparticles

“…184 as base and in the absence of solvent. 185 In 2014, Kotadia and Soni reported the synthesis of Fe-doped titania (Fe/TiO2) and silica (SiO2) NPs between 10-15 nm by sol-gel processes. 186 The NPs were used in A 3 -coupling reactions between an aldehyde, an amine and a terminal alkyne.…”

Silica‐supported Cu(II)–quinoline complex: Efficient and recyclable nanocatalyst for one‐pot synthesis of benzimidazolquinoline derivatives and 2H‐indazoles

“…In the past decade, a great deal of attention has focused on copper‐based nanocatalysts because of their high activity and selectivity in various organic reactions including multicomponent, cross‐coupling and click reactions . These Cu(II)‐based catalysts are readily available, of low cost, stable in air and can be easily handled in comparison to other transition metal catalysts .…”

“…In the past decade, a great deal of attention has focused on copper-based nanocatalysts because of their high activity and selectivity in various organic reactions including multicomponent, cross-coupling and click reactions. [1][2][3][4][5][6][7][8] These Cu(II)-based catalysts are readily available, of low cost, stable in air and can be easily handled in comparison to other transition metal catalysts. [9] Frequently, copper complexes with suitable and stable ligands including bipyridine, [10] dabco, [11] triazole dendrimer, [12] triazine-based polyethyleneamine dendrimer [13] and amidoxime [14] have been supported on various solid supports to efficiently perform organic reactions.…”

“…Moreover, multicomponent reactions have various benefits over traditional multistep synthesis including flexibility, simplicity, good yields, short reaction durations, high atom economy, avoidance of expensive purification and lower costs. [3][4][5][6]19,20] The synthesis and evaluation of hybrid molecules have been under continuing development because of their biological potential that includes anti-inflammatory, anticancer, anti-HIV, antidepressant and contraceptive activities. In this regard, there is an extensive potential for synthesizing new hybrid scaffolds to be utilized as building blocks for the next generation of pharmaceuticals.…”

Eco‐compatible three component strategies for C‐S bond formation in thioether and S‐aryl‐carbamodithioate compounds catalyzed by copper(II) nanoparticles supported on modified AlPO4

“…Based on our previous works on copper catalyzed organic reactions under green conditions, in the present study, we have investigated the covalent attachment of Cu(II) complex of 1,4‐dihydroxyanthraquinone to AlPO 4 nanoparticles and its applications as a novel nano‐catalyst for the green synthesis of thioether and S‐aryl‐carbamodithioate compounds through a three‐component C‐S bond formation reaction.…”