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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.

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.

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.

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, 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.