C–Se bonds in electron-rich arenes are easily formed by the reaction of bench-stable arylseleninic acids as an electrophilic selenium source. The only waste in the reaction is water.

The ability of chalcogenium salts to transfer an electrophilic moiety to a given nucleophile is well known. However, up to date, these reagents have been used in stoichiometric quantities, producing a substantial amount of waste as byproducts of the reaction. In this report, we disclose further investigation of selenonium salts as Sadenosyl-L-methionine (SAM) surrogates for the alkylation of nucleophiles in aqueous solutions. Most importantly, we were able to convert the stoichiometric process to a catalytic system employing as little as 10 mol % of selenides to accelerate the reaction between benzyl bromide and other alkylating agents with sodium cyanide in water. Probe experiments including 77 Se NMR and HRMS of the reaction mixture have unequivocally shown the presence of the selenonium salt in the reaction mixture.

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: For many years since its discovery, Selenium has played the role of a bad boy who became a hero in organic transformations. Selenium dioxide, for instance, is one of the most remembered reagents in allylic oxidations, having been applied in the synthesis of several naturally occurring products. The main goal of this review is to show the recent advances in the use of classical and new selenium reagents in organic synthesis. As demonstrated through around 60 references discussed in this study, selenium can go even forward as a versatile reagent. We bring a collection of selenium reagents and their transformations that are still hidden from most synthetic organic chemists.

Here, we describe a magnetic resonance spectroscopy characterization of selenium cyanide compounds, Se(CN)2, Se2(CN)2 and Se3(CN)2. Selenim-77 and carbon-13 nuclides were used to provide data of these species at room temperature. This is the first structural characterization performed using NMR for Se3(CN)2, while only low-temperature analyses have been conducted so far for Se(CN)2 and Se2(CN)2. Based on these limitations, a characterization study was deemed mandatory, especially from a synthetic chemistry point of view. In addition to these analyses, we carried out a purity assessment for Se3(CN)2 according to the melting point parameter along with a solubility evaluation.

Benzeneseleninic acid (BSA) derivatives were used as an alternative, but extremelly useful, source of Se(II)-based electrophiles, generated in situ by thermal decomposition, to construct C-Se bonds, accessing 3-selanylimidazopyridines after reaction...

Herein we describe a new method for the synthesis of α‐carbonyl selenocyanates by reacting triselenium dicyanide (TSD) and styrenes under blue light irradiation and O2 atmosphere. The reactions are triggered by the formation of Se‐centered radical species, followed by the addition/oxidation of the styrene π‐bond. α‐Carbonyl selenocyanates and α‐hydroxy selenocyanates were obtained in moderate to excellent yields from aryl‐ and alkyl‐substituted alkenes, respectively. It was demonstrated that α‐carbonyl selenocyanates could be used as a synthetic platform in a multicomponent reaction strategy to prepare 2‐phenylimidazo[1,2‐a]pyridine derivatives, which were evaluated for their photophysical properties. Overall, this new method provides a useful tool for synthesizing α‐carbonyl selenocyanates, demonstrating their potential for use in the synthesis of other compounds, and opening new synthetic opportunities to construct organic selenocyanate compounds.

Neglected tropical diseases (NTDs) affect mainly poor and marginalized populations of tropical and subtropical areas in 150 countries. Many of the chemical processes involved in the synthesis of active pharmaceutical ingredients (APIs) are highly polluting and inefficient, both in terms of materials and energy-consuming. In this review, we present the green protocols developed in the last 10 years to access new small molecules with potential applications in the treatment of leishmania, tuberculosis, malaria, and Chagas disease. The use of alternative and efficient energy sources, like microwaves and ultrasound, as well as reactions using green solvents and solvent-free protocols, are discussed in this review.