Cesium-catalyzed highly regioselective synthesis of (Z)-vinylic selenosulfides via thioselenation of alkynes with unsymmetrical diorganoyl dichalcogenides

Base-Catalyzed One-Pot Synthesis of Selenosulfides: A Base Basicity-Controlled Approach

We developed a novel and efficient sequential one-pot synthesis of selenosulfides via a base-catalyzed methodology utilizing readily available starting compounds, under mild reaction conditions. This method eliminated the need for excess oxidants or additives and simplified the synthesis procedure. Furthermore, organic amine bases served as exceptional catalysts for synthesizing the target products. The performance of a catalytic system depends on the basicity of the bases. The selection of suitable bases, based on their pKaH values, is crucial for the selective synthesis of selenosulfides without the formation of byproducts. This method provides a direct route for the preparation of selenosulfides, which are important scaffolds in organic chemistry.

Diorganyl diselenides: a powerful tool for the construction of selenium containing scaffolds

Organoselenium compounds find versatile applications in organic synthesis, materials synthesis, and ligand chemistry. Organoselenium heterocycles are widely studied agents with diverse applications in various biological processes. This review highlights the recent progress in the synthesis of selenium heterocycles using diorganyl diselenides with keen attention on green synthetic approaches, scopes, C-H selanylation, the mechanisms of different reactions and insights into the formation of metal complexes. The C-H selanylation using diorganyl diselenides with different catalysts, bases, transition metals, iodine salts, NIS, hypervalent iodine, and other reagents is summarised. Finally, the diverse binding modes of bis(2/4-pyridyl)diselenide with different metal complexes are also summarised.

Chemistry and Chemical Biology of Selenenyl Sulfides and Thioseleninic Acids

Significance: Selenenyl sulfides (RSeSRs) and thioseleninic acids (RSeSHs) are the monoselenium (Se) analogs of disulfides and persulfides that contain Se-S bonds. These bonds are found in several antioxidant-regenerating enzymes as derivatives of selenocysteine, making them an important player in redox biology as it pertains to sulfur redox regulation. Recent Advances: Mechanistic studies of redox-regulating selenoenzymes such as thioredoxin reductase and glutathione peroxidase suggest crucial Se-S bonds in the active sites. Peptide models and small-molecule mimics of these active sites have been prepared to study their fundamental chemistry. These advances help pave the road to better understand the functions of the Se-S bond in the body. Critical Issues: The Se-S bond is unstable at atmospheric temperatures and pressures. Therefore, studying their properties proposes a major challenge. Currently, there are no trapping reagents specific to RSeSRs or RSeSHs, making their presence, identity, and fates in biological environments difficult to track. Future Directions: Further understanding of the fundamental chemistry/biochemistry of RSeSRs and RSeSHs is needed to understand what their intracellular targets are and to what extent they impact signaling. Besides antioxidant regeneration and peroxide radical reduction, the roles of RSeSR and RSeSHs in other systems need to be further explored.

Direct cyanation, hydrocyanation, dicyanation and cyanofunctionalization of alkynes

In this review, direct cyanation, hydrocyanation, dicyanation, cyanofunctionalization and other cyanation reactions of alkynes were highlighted. Firstly, the use of nitriles and development of cyanation was simply introduced. After presenting the natural properties of alkynes, cyanation reactions of alkynes were classified and introduced in detail. Transition metal catalysed direct cyanation and hydrocyanation of alkynes gave alkynyl cyanides and alkenyl nitriles in good yields. Dicyanation of alkynes produced 1,2-dicyano adducts. Cyanofunctionalization of alkynes afforded functional cyanated compounds. Thiocyanation and selenocyanation yielded the expected functional vinylthiocyanates and vinylselenocyanates. A plausible reaction mechanism is presented if available.

Synthesis of cyclic phenyl hexayne from Me3Si-/Ph2P(O)-protected ethynes

A practical approach for the synthesis of cyclic phenyl hexayne is demonstrated through a one-pot deprotection/transformation of magnesium acetylide into a copper acetylide/Sonogashira coupling procedure, followed by dephosphination, Hay coupling, desilylation, and Eglinton coupling. This approach avoids tedious synthetic routes and harsh reaction conditions and affords the product in 41% yield.

Metal-free difunctionalization of alkynes leading to alkenyl dithiocyanates and alkenyl diselenocyanates at room temperature

A simple and practical method for the synthesis of alkenyl dithiocyanates and alkenyl diselenocyanates has been developed via stereoselective difunctionalization of alkynes with NaSCN or KSeCN at room temperature. Through this methodology, a series of alkenyl dithiocyanates and alkenyl diselenocyanates could be efficiently and conveniently obtained in moderate to good yields under mild and metal-free conditions by the simple use of oxone and PhI(OAc)2 as the oxidants.

AgBF4-catalyzed deoxygenative C2-amination of quinoline N-oxides with isothiocyanates

A general, effective and convenient protocol for the direct synthesis of various 2-aminoquinolines (39 examples) through AgBF₄-catalyzed amination of quinoline N-oxides with isothiocyanates under base-, oxidant-free and mild conditions was developed.

Direct synthesis of alkenyl iodides via indium-catalyzed iodoalkylation of alkynes with alcohols and aqueous HI

A simple and efficient method has been developed for the synthesis of alkenyl iodides through indium-catalyzed iodoalkylation of alkynes with alcohols and aqueous HI under mild conditions.