Highly Active and Efficient Cu@SiO₂ Catalyst: Enabled Nucleophilic and Electrophilic Activation of Active Methylene Compounds

Abstract

The utility of copper is strikingly afforded due to the variable oxidation state being widely used in various organic reactions. The copper-catalyzed CÀ C bond formation with active methylene compounds are a straightforward approach with widespread uses in synthetic organic chemistry. A significantly lower amount of Cu-supported SiO 2 catalyst was synthesized through sol-gel method. The microscopy analysis reveals the formation of spherical morphology and the uniform distribution of Cu nanoparticles of 2.5 nm size. Furthermore, copper was found in Cu + 2 state by XPS analysis. The NH 3 -TPD analysis estimated the 0.092 mmol/g acidic sites. The synthesized multifunctional catalyst was used for gabapentin intermediates through a series of active methylene compounds through tandem organic reactions. The catalyst gave excellent conversion (99%) and selectivity (99%) of the desired product. The catalyst was found to be highly stable and recycled for six cycles without losing any activity and selectivity to the reaction product.

Catalytic Valorisation of Biomass-Derived Levulinic Acid to Biofuel Additive γ-Valerolactone: Influence of Copper Loading on Silica Support

“…The catalyst's structure depends on factors such as copper loading, method of synthesis, and calcination conditions. Cu/SiO 2 catalysts exhibit excellent catalytic activity for various reactions, including hydrogenation, dehydrogenation, oxidation, and coupling reactions [10,[57][58][59][60]. The presence of Cu nanoparticles on the SiO 2 support enhances the catalyst's performance due to its high surface area and dispersion of active sites.…”

Cerium immobilized carbon nitride: A proficient and recyclable catalyst to construct carbon–carbon double bonds in water

“…[11] One such approach is the condensation between a carbonyl compound and an active methylene moiety-possessing molecule with the utilization of a wide variety of catalysts including mesoporous materials, metal-organic frameworks, bimetallic, mixed oxide, graphitic carbon nitride, and deep eutectic solvents. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] Further, hazardous solvents including tetrahydrofuran, [32,33] dimethyl formamide, [34] alcohols, [35,36] dioxane, [37] toluene, [38] acetonitrile, [39] and dichloromethane [40] have often been used to effect this carbon-carbon bond construction. [41][42][43][44][45][46][47] For instance, Hassan et al [41] showed the capacity of amino-grafted graphene oxide-Fe 3 O 4 in tetrahydrofuran at 50 C, Markad et al [44] exposed the performance of amidefunctionalized 2D coordination polymer (involving a bis-pyridylmethyldiaminobutane diacetamide) in methanol, Taher et al [45] revealed the amine-functionalized metal-organic framework in DMF, Zhong et al [46] discovered the utility of bifunctional mesoporous carbon nitride in toluene at 80 C under ...…”