L-proline-linked N-GQDs/ZnO/CuO Chiral Retrievable Catalyst: Synthesis, Characterization, and Investigation of Catalytic Performance in Diastereoselective Synthesis of Furocoumarin Natural Products

Abstract

The advancement of nanocatalysts for chemical reaction progress in conjunction with the green chemistry parameters has been widely considered today. Graphene Quantum Dots (GQDs) have been extensively investigated due to their interesting photochemical, and electrochemical properties. Besides, heteroatom doping is a smart technique to adjust the catalytic properties of GQDs. Nitrogen-doped GQDs (N-GQDs) have rarely been introduced in the catalysis field. Therefore, we proposed a hydrothermal route for the straightforward fabrication of N-GQDs/ ZnO/CuO heterojunction nanocomposites as an efficient nanocatalyst. Also, L-proline-linked N-GQDs/ZnO/CuO nanocomposites as a chiral retrievable catalyst in the synthesis of diastereoselective threecomponent reactions (4-bromophenacyl bromide, aromatic aldehydes, and 4-hydroxycoumarin) to afford of furocoumarins natural product. According to the obtained results, various parameters such as solvent, temperature, and pH range could control the nanocatalyst morphology. In the following, the catalytic activity of engineered heterojunction nanocomposite was screened in the one-pot diastereoselective synthesis of new and known furocoumarin derivatives natural product. During the three-component reaction progress, three new sigma bonds (two C-C and one C-O) were formed which led to the formation of the products in excellent yields (86-96 %) in a short time. Also, to achieve the highest catalytic efficiency, the influence of main parameters such as temperature, solvent, and the molar ratio of the nanocomposites were optimized. High diastereoselectivity, good to excellent atom economy, very short reaction time (35 min), reusability of catalyst (7 times), and a bit catalyst loading can be cited as the other notable features of this strategy