Electrochemistry of Organic Selenium and Tellurium Compounds

Abstract

Electrochemical synthesis of organic selenium and tellurium compounds as well as different mechanisms of their anodic and cathodic reactions were reviewed. The first part includes the review of the direct synthesis of the title compounds from the elemental selenium and tellurium, the synthesis by anodic reactions using mainly the generation of arylselenium or tellurium cations and the cathodic reduction based on the generation of organoselenium and tellurium anions. These synthetic applications, more interesting for the wider group of organic chemists, are discussed in more detail. Examples of the anodic functionalization (such as acetoxylation or fluorination) leading to new organic chalcogen compounds are also given. The detailed discussion of the anodic behavior of the title compounds is divided into separate parts, each of them devoted to the different class of compounds. They include first of all diaryl, dialkyl and alkylarylselenides and tellurides, most widely investigated for many years, and next diaryl and dialkyl diselenides. However, anodic reactions of some typical heterocyclic selenides and tellurides are also briefly reviewed. Some electrode reactions in which the title compounds play only the role of intermediates are mentioned as well. Finally, electroreduction mechanisms of organoselenium and tellurium compounds are discussed.

Electrochemical synthesis of organochalcogenides in aqueous medium

“…The reaction with the S 2− ion gave the corresponding sulfide in moderate yield and selectivity, where dibenzylsulfide 2o was obtained in 56% yield together with 9% of dibenzyldisulfide (Table 2, entry 15). When the sterically hindered 1-bromo-adamantane was used as the substrate the reaction was not effective to promote the synthesis of chalcogenides (Table 2, entries [16][17][18]. The same behavior was also observed when the aryl halides bromobenzene and iodobenzene were used as the reaction electrophiles ( The developed method is interesting not only due to its simplicity, but also because it allows monitoring the formation of the desired anions.…”

“…Electrochemistry provides a feasible alternative for organochalcogenide synthesis, since the use of electrochemical techniques is gaining more space as an efficient method of synthesis, in particular due to the high yield of products, current efficiency and control of the process; therefore, cleaner, faster and cheaper processes can become economically and environmentally viable by using electrochemical procedures. 18 The electrochemical synthesis of diaryldichalcogenides (Se and Te) was described by a SNR1 reaction mechanism of aryl halides using sacrificial cathodes (Se and Te) in aprotic medium (acetonitrile, DMSO and DMF).…”

Organoselenium Compounds in Catalysis

“…Including its important role in medicinal chemistry, [37][38][39][40][41] organoselenium compounds not only show interesting chemical properties, but also their use in catalysis is very relevant and supported by copious bibliography. [42][43][44][45][46][47] In fact, the use of organoselenium compounds as promoters in a number of organic reactions has been established. 42 In this sense, considering the significance of having at hand organoselenium compounds to be used as a catalyst or even precatalyst, a number of synthetic approaches to access diverse selenium-containing molecules have been reported.…”

Green Organoselenium Chemistry: Selective Syntheses of New 1,4-Thiaselenine Derivatives Based on Reactions of Thiaselenole Reagent with Alcohols and Water

“…It is known that selenium is an indispensable trace element for humans and mammals [1][2][3][4]. After the discovery of the important biological role of selenium [4], organoselenium chemistry developed rapidly [5][6][7][8]. It has been established that organoselenium compounds exhibit various types of biological activities [9][10][11][12][13][14][15][16][17][18] including antitumor [9][10][11][12], antibacterial [12,13], antiviral [14,15], and glutathione peroxidase-like properties [16][17][18].…”

“…77 Se NMR (CDCl 3 , 76.3 MHz): δ 224.7 (cyclic), 229.4. MS (EI), m/z (%): 403(5) [M] +• , 223(7), 196 (3), 165(38), 87 (100), 59(40) 1. …”