Mechanochemical synthesis of organoselenium compounds

We disclose herein a strategy for the rapid synthesis of versatile organoselenium compounds under mild conditions. In this work, magnesium-based selenium nucleophiles are formed in situ from easily available organic halides, magnesium metal, and elemental selenium via mechanical stimulation. This process occurs under liquid-assisted grinding (LAG) conditions, requires no complicated pre-activation procedures, and operates broadly across a diverse range of aryl, heteroaryl, and alkyl substrates. In this work, symmetrical diselenides are efficiently obtained after work-up in the air, while one-pot nucleophilic addition reactions with various electrophiles allow the comprehensive synthesis of unsymmetrical monoselenides with high functional group tolerance. Notably, the method is applied to regioselective selenylation reactions of diiodoarenes and polyaromatic aryl halides that are difficult to operate via solution approaches. Besides selenium, elemental sulfur and tellurium are also competent in this process, which showcases the potential of the methodology for the facile synthesis of organochalcogen compounds.

Manganese-promoted reductive cross-coupling of disulfides with dialkyl carbonates

Manganese is a cheap and environmentally friendly metal on Earth. Herein, we report a manganese-promoted reductive cross-coupling using easily available and odorless disulfides as thiolating agents in an excellent 100% sulfur atom economy. The protocol featured a broad substrate scope, including various alkyl disulfides and excellent functional group compatibility, constructing diverse thioethers under simple conditions. Ultimately, thioethers can be prepared in gram-scale reactions and further transformed into structurally complex molecules.

Copper-Catalyzed Cascade Multicomponent Reaction of Azides, Alkynes, and Selenium: Synthesis of Ditriazolyl Diselenides

A copper-catalyzed cascade multicomponent reaction for synthesizing ditriazolyl diselenides from azides, terminal alkynes, and elemental selenium has been developed. The present reaction features utilizing readily available and stable reagents, high atom-economy, and mild reaction conditions. A possible mechanism is proposed.

Highly efficient synthesis of diselenides and ditellurides catalyzed by polyoxomolybdate-based copper

A polyoxomolybdate-based copper-catalyzed synthesis of diselenides and ditellurides from organic iodides and elemental selenium or tellurium in moderate to excellent yields is developed.

Transition Metal Catalyst, Solvent, Base Free Synthesis of Diaryl Diselenides under Mechanical Ball Milling

A convenient, efficient, and general procedure for the synthesis of diaryl diselenides has been developed by the reaction of aryl diazonium tetrafluoroborates and Potassium Selenocyanate on the surface of alumina under ball-milling in absence of any solvent, transition metal catalyst and base in room temperature. A wide range of functionalized diaryl diselenides are obtained in high purity and high yield by this procedure.

BACKGROUND

Synthesis of diaryl diselenides was restricted into only few Cu-catalyzed C-Se Cross coupling protocol where use of ligands, high reaction temp, long reaction time were required.

OBJECTIVE

To achieve a sustainable protocol for the synthesis of diaryl diselenides Method: Reaction of aryl diazonium fluoroborate with KSeCN was successfully performed under ball milling in absence of any ransition metal catalyst, ligands, base and external heating to get diaryl diselenides.

RESULTS

A library of diaryl diselenides were obtained in good yields with different functional groups.

CONCLUSION

First transition metal free protocol for the synthesis of diaryl diselenides has been developed successfully.

A recyclable heterogeneous nanocatalyst of copper-grafted natural asphalt sulfonate (NAS@Cu): characterization, synthesis and application in the Suzuki–Miyaura coupling reaction

NAS@Cu has synthesis simplicity given the availability of natural materials and has advantages such as being eco-friendly, high reactivity and recyclability.

Unsymmetrical Disulfides Synthesis via Sulfenium Ion

An umpolung approach for the synthesis of unsymmetrical disulfides via sulfenium ion is reported. In situ generated electrophilic sulfenium ion from electron-rich thiols reacted with second thiols to yield unsymmetrical disulfides. Using an iodine catalyst and 4-dimethylaminopyridine (DMAP)/water as promoter, the target syntheses were achieved in one pot under aerobic condition.

Incorporation of CuO NPs into modified UiO-66-NH2 metal–organic frameworks (MOFs) with melamine for catalytic C–O coupling in the Ullmann condensation

The UiO-66-NH₂ is initially modified with melamine via a post-synthetic approach. CuO NPs are then anchored via the available functional groups on the surface of the modified MOF.

Aryl diazonium salt and thioacetamide: a catalyst free, efficient blend of an inexpensive arylating agent with “S” surrogate for sulphide synthesis

Metal free, chemoselective method for C–S, S–S bond formation reactions.

Efficient and recyclable copper-based MOF-catalyzed N-arylation of N-containing heterocycles with aryliodides

Copper-based MOF-199 was used as an efficient heterogeneous catalyst to catalyze cross-coupling reactions between N-containing heterocycles and aryliodides with high yields.