Heterogeneous copper-catalyzed C S coupling via insertion of sulfur dioxide: A novel and regioselective approach for the synthesis of sulfur-containing compounds

Polyoxometalate-based ionic liquids: efficient reversible phase transformation-type catalysts for thiolation of alcohols to construct C-S bonds

As important building blocks in natural products and organic synthesis, thioethers have a wide range of potential applications. Herein, polyoxometalate-based ionic liquids (POM-ILs-SO3H) derived from N-alkyl imidazole were synthesized and used for the first time for the thiolation of alcohols to construct C-S bonds in a series of benzyl thioethers. This type of POM-ILs-SO3H catalyst exhibited high catalytic activity, providing up to 98% yield of thioether within 1 h at 70 °C. The alkyl chain length of the imidazole had a certain effect on the solubility of the POM-ILs-SO3H catalysts in the reaction solvent, and then affected their catalytic activity. The catalytic system had a wide substrate scope and was suitable for the reaction of tertiary and secondary benzyl alcohols with thiophenols or cycloalkyl thiols. In particular, [PIMPS]3PW12O40 (PIM = 1-propylimidazole, PS = propane sulfonate) as a reversible phase transformation-type catalyst, combining the advantages of homogeneous and heterogeneous catalysts, exhibited high activity and good recyclability with only a slight decrease in the yield after five runs. Additionally, a carbocation mechanism was proposed for the thiolation reaction of alcohols.

Merging cobalt and photoredox catalysis for the C8-H alkoxylation of 1-naphthylamine derivatives with alcohols

A combined cobalt and photoredox catalysis system to realize the C8-H alkoxylation of 1-naphthylamine derivatives with alcohols was developed. Using commercially available alkyl alcohols as raw materials and Co(OAc)₂ and rose bengal as catalysts, 1-naphthylamine derivatives reacted with alcohols to generate the corresponding C8-H alkoxylation products in good yields.

Oxidative Sulfonylation of Hydrazones Enabled by Synergistic Copper/Silver Catalysis

A copper/silver-cocatalyzed protocol for oxidative sulfonylation of hydrazones is demonstrated. A wide range of β-ketosulfones and N-acylsulfonamides are directly synthesized in moderate to good yields. Our work provides a viable method for scalable preparation of β-ketosulfone derivatives that have found wide applications in the pharmaceutical industry.

Generation of (Z)-β-alkenyl alkylsulfones via a copper-catalyzed decarboxylative alkylsulfonylation

A copper-catalyzed three-component reaction of acrylamides, sulfur dioxide and phenyliodine(iii) dicarboxylates is developed. The conversion using phenyliodine dicarboxylates as alkyl radical precursors provides diverse (Z)-β-alkenyl alkylsulfones.

Transition-metal- and oxidant-free three-component reaction of quinoline N-oxides, sodium metabisulfite and aryldiazonium tetrafluoroborates via a dual radical coupling process

A convenient and straightforward three-component transformation of quinoline N-oxides, sodium metabisulfite and aryldiazonium tetrafluoroborates has been developed, providing the target products in moderate to good yields. Compared with previous studies, the present methodology avoids the use of transition-metal catalysts and excess oxidants, providing a simple and practical alternative approach for the construction of 2-sulfonylquinolines. Control experiments indicate that a dual radical coupling process is responsible for this reaction.