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The photocatalyzed synthesis of silanols from tertiary si­lanes has been carried out using eosin Y under air. This is a metal-free method that uses a low catalyst loading, atmospheric oxygen as the oxidant, and visible-light conditions (blue light).

Sulfur-containing compounds are one of the most common and important heteroatom skeletons and are widely found in natural products, pharmaceuticals and bioactive compounds. Moreover, the development of the synthetic routes to organosulfur compounds have attracted a considerable attention due to their widely application in organic chemistry, pharmaceutical industry and materials science. As one of most powerful, green and eco-friendly research areas, organic electrosynthesis could avoid the use of harmful stoichiometric external oxidants or reductants, compared with conventional organic synthesis. Importantly, halide salts are widely used as supporting electrolyte and redox catalysts in indirect electrosynthesis to avoid the limitations imposed by high overpotentials in direct electrosynthesis. In recent years, great progress has been made in the halogen-mediated electrosynthesis of organosulfur compounds. In this minireview, the scope, limitations and mechanisms of halogen-mediated electrochemical transformations of sulfur-containing compounds are presented and discussed.

A mild, radical cascade cyclization of N-arylacrylamides with diselenides for the preparation of oxindoles via iodine oxidation is disclosed that provides an environmentally friendly process for the construction of C–Se bonds. Twenty-five examples of N-arylacrylamide substrates were investigated, and excellent yields were achieved. The tandem cyclization of acrylamide with diphenyl disulfide was also applicable under the same conditions.

An electrochemical oxidative synthesis of S-thiocarbamates by carbamothioation reaction via a three-component coupling reaction (disulfide, water and isocyanide) is developed, which avoids using external oxidants and generates only hydrogen gas as the by-product. With NH4I as the mediator and electrolyte, the desires S-thiocarbamates were prepared in good yields in an undivided cell at room temperature.

We report a novel, inexpensive double thiolation reagent that sulfurizes a broad range of imidazo[1,2-α]pyridines under mild conditions. Importantly, diethylaminosulfur trifluoride, as a common nucleophilic fluorinating reagent, was utilized as a novel thiolation reagent.

Bromoaryl compounds have attracted great attention in organic chemistry, especially for the synthesis of pharmaceutical intermediates. Herein, we demonstrated a novel and efficient bromination protocol of indazoles

An efficient and eco-friendly protocol for synthesizing difluoromethylated oxindoles through a visible-light induced one-pot tandem reaction of N-arylacrylamides, difluoroacetic acid and PhI(OAc)2 was developed. This reaction proceeded in the absence of any additive, base, metal-catalyst and external photosensitizer, using cheap and easily available CHF2CO2H as the difluoromethylation reagent and bulk biomass-derived 2-MeTHF as the sole solvent. 26 Examples of N-arylacrylamide substrates were investigated, and all of them successfully underwent difluoromethylation to deliver the target products in good to excellent yields.

An eco-friendly, sustainable and practical method for the efficient preparation of 5-organylselanyl uracils through the electrochemical selenylation of uracils and diorganyl diselenides at room temperature under oxidant- and external electrolyte-free conditions was developed.

With green ethanol as the sole solvent, various 3-aminomethylated imidazoheterocycles were efficiently synthesized in one step through a four-component reaction of equimolar cheap and commercially available reactants at ambient temperature under metal-free, oxidant-free and mild conditions.

An energy-saving and eco-friendly method for the efficient construction of various tri- and tetra-substituted pyrrolecarbonitriles through ultrasound-assisted multicomponent tandem reaction of readily available alkenes, TMSCN and N,N-disubstituted formamides within 40 min under metal-, solvent-free and mild conditions was developed. The dual role of iodine (catalyst and oxidant) notably simplified the reaction conditions and reduced the chemical waste generated

By using pyridinium tribromide as the bromo source, an efficient­ and practical protocol for the synthesis of C3-brominated imidazo­[1,2-a]pyridines through ultrasound-promoted and Na2CO3-mediated regioselective bromination of imidazo[1,2-a]pyridines has been developed. This method effectively avoids the use of metal catalysts and harsh reaction conditions, and shows attractive characteristics such as operational simplicity, broad substrate scope with good to excellent yields, ease of scale-up and high energy efficiency.

A catalyst-, oxidant-, electrolyte-free method for the preparation of α-ketoamides through the direct electrochemical amidation of α-ketoaldehydes and amines with innocuous hydrogen as the sole byproduct at ambient temperature was developed. The present reaction features clean and mild conditions, excellent functional-group tolerance, and high atom economy and scalability, enabling facile applications in pharmaceutical chemistry.

With eco-friendly and sustainable CO2 -derived dimethyl carbonate as the sole solvent, the visible-light-induced cascade radical reactions have been established as a green and efficient tool for constructing various CHF2 /CClF2 /CBrF2 -substituted ring-fused quinazolinones.

With eco-friendly and sustainable CO

A visible-light-promoted radical cascade reaction of

A practical and sustainable protocol for the clean preparation of various multisubstituted pyrroles through an iodine-catalyzed multicomponent reaction under metal- and solvent-free conditions was developed. In the gram-scale synthesis, the desired pyrroles can be easily isolated in high-purity through simple extraction.

In this work, a variety of α-cyanopyrrolines were efficiently synthesized from alkenes, TMSCN and N,N-disubstituted formamides via molecular iodine-catalyzed tandem reaction under neat and mild conditions. This method applies ambient air as the sole oxidant and circumvents the use of transition metals and extra solvents to afford a broad range of final products with good regio- and chemo-selectivity.

A novel Cu(i)-catalyzed intermolecular cyanoarylation of alkenes with diaryliodonium salts as a radical arylating reagent and tetra-butylammonium cyanide as an electrophilic cyanating reagent was established. A broad range of α-alkylated arylacetonitriles were efficiently constructed in good to excellent yields under base- and oxidant-free and mild conditions.

A novel metal catalyst-free and environmentally friendly method for the regioselective iodination of imidazo[1,2-α]pyridines at their C3 position is disclosed, which has a wide substrate scope and could be sustainable. This reaction proceeds through ultrasound acceleration in the presence of a green alcohol solvent. Compared with a conventional heating system, the reaction efficiency and the rate are significantly improved and the iodine atom economy is maximized using ultrasound techniques.

The desymmetrization of prochiral 4,4-disubstituted cyclopentenes via a site-selective copper-catalyzed allylic oxidation is described. This study provides a direct comparison of a series of known methods for allylic oxidation, and thus identifies ligand-free copper(i) iodide as the optimal catalyst for this particular process. Notably, this work offers a convenient approach to the preparation of γ-quaternary α,β-unsaturated cyclopentenones, which permits an efficient three-step total synthesis of (±)-untenone A.

A novel, sustainable, environmentally friendly, high substrate scope, efficient, solvent-free and metal catalyst-free method for the cross-dehydrogenative coupling (CDC) reaction between N-hydroxyphthalimide (NHPI) and benzyl/ether compounds is described. This coupling reaction proceeds through ultrasound acceleration. Compared to conventional heating conditions, the use of ultrasound techniques not only improves the reaction efficiency and enhances the reaction rate but also minimizes the side reactions.

Synthesis of diversely functionalized symmetrical benzidines through electrochemical dehydrogenative cross-coupling reaction of two N,N-disubstituted anilines, is described. The reactions conducted under mild conditions with no oxidizing reagents and transition metal catalysts.

An efficient and highly E-selective protocol for the synthesis of vinyl sulfones is described. This simple protocol demonstrates the first synthesis of vinyl sulfones via a silver-catalyzed C-S bond coupling reaction. In addition, the success of the reaction was found to be critically dependent on the use of TEMPO as the additive.