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.

No abstract

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.

: 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.

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.