Exclusive Review Papers in Catalysis in Organic and Polymer Chemistry

In advanced organic chemistry and polymer chemistry, catalysts are recognized as fundamental to making reactions selective, efficient, and achievable in a single step. The presence of the catalyst in synthetic processes also allows for the realization of reactions in highly sustainable conditions [1]. In this Special Issue, nine exclusive review papers are reported in this field.

In the first review, A. Moya et al. describe synthetic strategies for the production of chiral materials, generally porous organic frameworks, including crystalline (covalent organic frameworks, COFs) and amorphous (conjugated microporous polymers, CMPs; covalent triazine frameworks, CTFs; and porous aromatic frameworks, PAFs) compounds, the evaluation of their chirality, and their applications in asymmetric organocatalytic reactions [Contribution 1].

In the second contribution, P. Vitale et al. report the use of deep eutectic solvents (DESs) as catalysts or as reaction medium on the chemical recycling of Polyethylene terephthalate (PET), Polyurethane (PU), Poly(ethylene 2,5-furandicarboxylic acid) (PEF), Polycarbonate (PC), Polylactic acid (PLA), and other widely used polymeric materials. DESs are used also in combination with microwave irradiation (MW), biocatalysts, Lewis acid catalysts; fine chemicals, monomers, or other polymers are obtained, such as products [Contribution 2].

B. Gabriele et al., in the third contribution, report an overview of catalytic carbonylative double cyclization reactions for constructing polycyclic heterocyclic derivatives. Suitable organic substrates and carbon monoxide are activated by a catalyst to form two fused cycles with the incorporation of carbon monoxide in the final polycyclic heterocyclic products [Contribution 3].

A review of metal-catalyzed cascade reactions between alkynoic acids and dinucleophiles (C-, N-, O- and S-aminonucleophiles) for the synthesis of complex polycyclic structures is provided by R. SanMartin et al. In this field, copper (II) salt, ruthenium carbenes, iron salts, and palladium (II) complexes catalysts have recently been added to the most widely used gold (I) complexes and silver (I) salts catalysts, showing an excellent catalyst profile in the reaction of alkynoic acids and dinucleophiles (C-, N-, O- and S-aminonucleophiles). The exception is ruthenium carbenes, unable to promote the reaction with C-aminonucleophiles, limiting the reaction to N-, O- or S-aminonucleophiles [Contribution 4].

In the fifth review V. Cadierno et al. describe the synthetic strategies reported in the literature aimed at functionalizing hydrophilic N-Heterocyclic Carbens (NHCs) ligand with gold complexes for the production of NHC-gold catalysts. Water-soluble gold nanoparticles, stabilized by hydrophilic NHCs, catalyze Markovnikov hydration of terminal alkynes, reduction of nitroaromatic compounds and cyclization reactions of functionalized alkynes and allenes. NHC-gold catalysts could be recovered and reused by extraction of the products from the aqueous phase [Contribution 5].

The study and use of Hantzsch esters (1,4-dihydropyridine dicarboxylates) in organocatalytic enantioselective synthesis are reported by J. L. Poimbiero et al. in the sixth review. The authors show that Hantzsch esters are good reagents for the dearomatization of heteroaromatic compounds, useful reagents for photoredox reactions and excellent hydride transfer agents to reduce multiple bonds. On the other hand, Hantzsch esters can participate readily in cascade processes [Contribution 6].

J.-M. Campagne et al. describe, in the seventh review, catalytic formation of amide bonds by direct catalytic amidations from amines and carboxylic acids or esters, highlighting novel technologies, practicability, scalability, limitations in substrate and mechanistic aspects [Contribution 7].

In the eighth contribution, L. A. Aronica et al. present the immobilization of palladium nanoparticles on natural biomaterials, afterwards applied to the formation of C–C bonds by Sonogashira, Suzuki–Miyaura and Mizoroki–Heck reactions. The authors describe cellulose, starch, pectin, agarose, chitosan, proteins and enzymes as very good supports for heterogeneous palladium catalysts [Contribution 8].

In the ninth and final review, various methods for the preparation of ZnO reinforced polymer composites are presented. M. J. Mochane et al. describe the morphology and the photocatalytic activity of various ZnO/polymer composites and the morphology and the photocatalytic activity of ZnO blended with other nanoparticles (Ag, TiO₂, CuO, Fe₃O₄), incorporated into the polymer matrices [Contribution 9].