Reactions of alkynes with C-S bond formation: recent developments.

Alkynes are important in organic synthesis. This review mainly focuses on recent advances (2013-2023) on alkynes with C-S bond formation, based on more than 30 types of sulfur reagents. The reactions of alkynes with various sulfur-containing compounds including RSSR (disulfides), RSH (thiols), S8 (elemental sulphur), alkynyl thioethers, RSCN, AgSCF3, K2S, Na2S, dithiane, RSCl, NFSI, RNCS, EtOCS2K, thiocarbamate, RSONH2, thiourea, sulfoxide, RSO2N3, CS2, RSO2NH2, RSO2NHNH2, RSO2Cl, RSO2Oar, RSO2SR', DABCO·(SO2)2, Na2S2O5, K2S2O5, RSO2H, RSO2Na and related compounds are discussed. Diverse mechanisms such as radical, electrophilic/nucleophilic addition, rearrangement, C-C bond cleavage, and CuAAC are discussed. The content is organized by substrates and reactivity patterns. We hope it will help in future research in this area.

Development of Synthesis and Application of High Molecular Weight Poly(Methyl Methacrylate).

Poly(methyl methacrylate) (PMMA) is widely used in aviation, architecture, medical treatment, optical instruments and other fields because of its good transparency, chemical stability and electrical insulation. However, the application of PMMA largely depends on its physical properties. Mechanical properties such as tensile strength, fracture surface energy, shear modulus and Young's modulus are increased with the increase in molecular weight. Consequently, it is of great significance to synthesize high molecular weight PMMA. In this article, we review the application of conventional free radical polymerization, atom transfer radical polymerization (ATRP) and coordination polymerization for preparing high molecular weight PMMA. The mechanisms of these polymerizations are discussed. In addition, applications of PMMA are also summarized.

New type of borneol-based fluorine-free superhydrophobic antibacterial polymeric coating.

A new type of superhydrophobic borneol-based polymeric coating has been prepared. The chemical composition of the polymer particles was analyzed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, which showed that the polymer did not contain fluorine, which can effectively avoid the cytotoxic risk of fluorine. By dynamic light scattering, scanning electron microscopy, and static contact angle measurement, the contact angle of the prepared coating gradually increased with increasing diameter of the polymer particles, and a superhydrophobic coating surface was finally obtained. Interestingly, after dissolving the superhydrophobic sample with tetrahydrofuran and making it a normal hydrophobic sample, the antiadhesion performance for E. coli was greatly reduced, and it could not effectively prevent E. coli adhesion. In addition, a long-term antiadhesion study of bacteria was performed. The superhydrophobic borneol-based polymer coating showed long-term resistance to E. coli adhesion. Therefore, the excellent antibacterial properties and cell compatibility mean that this series of polymer materials has great potential in the field of biomedicine.

Direct halosulfenylation of benzo[b]furans: a metal-free synthesis of 3-halo-2-thiobenzo[b]furans.

The first example of the direct halosulfenylation of benzo[b]furans with commercially available disulfides and N-halosuccinimides has been achieved, providing an efficient metal-free synthetic pathway to access diverse 3-halo-2-thiobenzo[b]furans in moderate to excellent yields. In particular, a halogen (e.g., bromo or iodo) substituent on the benzo[b]furan ring is amenable for further synthetic elaborations thereby broadening the diversity of the products.

N-Sulfonyl acetylketenimine as a highly reactive intermediate for the synthesis of N-sulfonyl amidines.

A highly reactive intermediate N-sulfonyl acetylketenimine was generated from a 3-butyn-2-one participating CuAAC/ring-opening method. Its high reactivity due to bearing two EWGs allowed us to offer the first example of a reaction between ketenimine and amide to synthesize N-sulfonyl amidines efficiently.

Tandem Synthesis of α-Diazoketones from 1,3-Diketones.

A highly efficient synthesis of α-diazoketone was achieved by simply stirring the mixture of 1,3-diketone, TsN3, and MeNH2 in EtOH. It was a tandem reaction including a novel primary amine-catalyzed Regitz diazo transfer of 1,3-diketone and a novel primary amine-mediated C-C bond cleavage of 2-diazo-1,3-diketone.

Copper-mediated trifluoroacetylation of indoles with ethyl trifluoropyruvate.

Direct trifluoroacetylation of indoles with ethyl trifluoropyruvate as a trifluoroacetylating reagent has been developed. This novel protocol provides an attractive route for the preparation of 3-trifluoroacetylindole derivatives, due to its operational simplicity and practicability as well as mild reaction conditions.

Recent advances in reactions of aryl sulfonyl isocyanates.

Aryl sulfonyl isocyanates are important intermediates in organic synthesis. They are used as electrophilic reagents and easily react with nucleophiles to form amides, sulfonyl ureas, pyrrolidine derivatives, lactams, oxazolidinones, and so on. Although there are some reviews on the applications of isocyanates in chemistry, few are concerned about aryl sulfonyl isocyanates. This review focuses on recent advances related to aryl sulfonyl isocyanates in organic synthesis, mainly including three special characteristics. The mechanisms of the typical reactions are also discussed.

Synthesis of N-Sulfonyl Arylaldimines Developed by Retesting an Old Process.

By simply heating the mixture of an arylaldehyde and a sulfonylisocyanate in a solvent or in neat form under catalyst- and additive-free conditions, the desired N-sulfonylimine was produced with the release of carbon dioxide. The method is characterized by its unique clean efficiency, convenience, and scalability, but it was reported to fail half a century ago.

Tandem synthesis of 3-halo-5-substituted isoxazoles from 1-copper(I) alkynes and dihaloformaldoximes.

A tandem synthesis of 3-halo-5-substituted isoxazoles has been developed from 1-copper(I) alkynes and dihaloformaldoximes under base-free conditions. Thus, 1,3-dipolar cycloaddition and all its drawbacks can now be avoided completely.