Tellurium-containing Thiol-peroxidase-like Antioxidants and their Catalytic Mechanism

Abstract: The development of novel small molecules with effective catalytic antioxidant properties is highly sought after. A wide array of structurally diverse selenium- and tellurium-containing glutathione peroxidase mimics have been studied over the past two decades. Within this arena, organotellurium compounds generally exhibit higher catalytic properties with respect to selenium-containing analogues. Different mechanisms accounting for the thiol-peroxidase-like activity of various classes of organotellurium derivatives have been proposed. This review documents developments in this area and provides an overview of the catalytic mechanisms proposed for the various classes of telluriumcontaining thiol-peroxidase-like-catalysts. </jats:sec

The Chemistry of Selenosilanes: A Topic Overview

Selenium-containing molecules represent a valuable class of compounds with a variety of applications in chemical and biological fields. Selenated reagents are used as intermediates to introduce functional groups (e.g., double bonds) onto different substrates or in the synthesis of various selenated derivatives. Among the variety of selenium-containing reagents, silyl selenides are frequently used to transfer a selenated moiety due to the smooth functionalization of the Se-Si bond, which allows for the generation of selenium nucleophilic species under mild conditions. While the use of the analogous sulfur nucleophiles, namely silyl sulfides, has been widely explored, a relatively limited number of reports on selenosilanes have been provided. This contribution will focus on the application of selenosilanes as nucleophiles in a variety of organic transformations, as well as under radical and redox conditions. The use of silyl selenides to prepare metal complexes and as selenium precursors of materials for atomic layer deposition will also be discussed

Unexpected ethyltellurenylation of epoxides with elemental tellurium under lithium triethylborohydride conditions

The one-pot multistep ethyltellurenylation reaction of epoxides with elemental tellurium and lithium triethylborohydride is described. The reaction mechanism was experimentally investigated. Dilithium ditelluride and triethyl borane, formed from elemental tellurium and lithium triethylborohydride, were shown to be the key species involved in the reaction mechanism. Epoxides undergo ring-opening reaction with dilithium ditelluride to afford β-hydroxy ditellurides, which are sequentially converted into the corresponding β-hydroxy-alkyl ethyl tellurides by transmetalation with triethyl borane, reasonably proceeding through the SH2 mechanism