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Herein, we report our investigations on the biomimetic bromofunctionalization of aromatic and heteroaromatic compounds using NaBr as a source of bromine, 30% (w/v) H2O2 as an oxidant, and SeCl4 as a commercially available catalyst in water without a co-solvent. Under these mild conditions, brominated (hetero)aromatic compounds were obtained in reasonable yields. In addition, 77Se NMR experiments were performed to provide experimental support for the proposed mechanism of the developed halofunctionalization reaction. [ABSTRACT FROM AUTHOR]

We have developed an approach for the construction of naphthofuran‐2‐carboxaldehyde derivatives utilizing the synergy of electrochemical oxidation and organo‐selenium catalysis at room temperature. The compatibility of various functional groups and scalability of this protocol demonstrate the practicality of the electrochemical strategy. The synthetic utility of this strategy is furthermore demonstrated by synthesizing diversified molecules through downstream transformations. [ABSTRACT FROM AUTHOR]

Vinylsilanes and vinylboronates are common building blocks for organic synthesis, but direct functionalization of these species without the participation of either the C=C or C−Si/B bonds is rare. Herein, we report a metal‐free allylic C−H amination reaction of these vinylmetalloid species that installs a new C−N bond without competing transmetallation or alkene addition. In this transformation, the silicon or boron substituent inverts the usual regioselectivity, directing amination to the site distal to that group. Subsequent cross‐coupling or demetallation allows access to complementary regioisomeric products. Density Functional Theory computations revealed that the observed regioselectivity is due to a subtle combination of electronic and counterintuitive steric factors that favor initial attack of selenium at the silicon‐bearing carbon atom. [ABSTRACT FROM AUTHOR]

Abstract A biomimetic iodofunctionalization of aromatic and heteroaromatic compounds has been developed using NaI as a source of iodine and 30% H2O2 as a mild oxidant, as well as SeCl4 as a commercially available catalyst in water without a co-solvent. The method affords iodinated compounds in isolated yields of 37 to 99%. The catalytic system has potential for the bromination of aromatic substrates.

A convenient method for the synthesis of polyanilines was developed through the organoselenium-catalyzed oxidation of anilines with H2 O2. Unlike reported methods, this reaction generates no wastes other than water. These green features make the method much more practical in terms of large-scale preparation. Moreover, it is the first example of an application of organoselenium catalysis techniques in aniline polymerization reactions and might be an important advance in the fields of both organoselenium catalysis and polyanilines. [ABSTRACT FROM AUTHOR]

A suitable oxidative system is crucial to electrophilic selenium catalysis (ESC). This short review offers the overview of recent development in ESC with electrophilic N-F reagents as the oxidants. Several highly selective transformations of alkenes such as allylic or vinylic imidation, pyridination, syn-dichlorination, oxidative cyclization and asymmetric cyclization have been described. [ABSTRACT FROM AUTHOR]

An efficient selenium-catalyzed direct oxidation of benzylpyridines in aqueous DMSO has been successfully developed by using molecular oxygen as the oxidant. A variety of benzoylpyridines with broad functional group tolerance were obtained in modest to excellent yields and with exclusive chemoselectivity. [ABSTRACT FROM AUTHOR]

An efficient approach for organoselenium-catalyzed regioselective C−H pyridination of 1,3-dienes to form pyridinium salts has been developed. This method was also successfully applied to direct C−H pyridination of alkenes. Fluoropyridinium reagents, or initially loaded pyridine derivatives, acted as pyridine sources in the pyridination reactions. The obtained pyridinium salts could be further converted under different conditions. This work is the first example of catalytic C-2 direct C−H functionalization of 1,3-dienes and the first case of organoselenium-catalyzed C−H pyridination. [ABSTRACT FROM AUTHOR]

Glutathione peroxidases (GPxs) are enzymes working with either selenium or sulfur catalysis. They adopted diverse functions ranging from detoxification of H 2 O 2 to redox signaling and differentiation. The relative stability of the selenoenzymes, however, remained enigmatic in view of the postulated involvement of a highly unstable selenenic acid form during catalysis. Nevertheless, density functional theory calculations obtained with a representative active site model verify the mechanistic concept of GPx catalysis and underscore its efficiency. However, they also allow that the selenenic acid, in the absence of the reducing substrate, reacts with a nitrogen in the active site. MS/MS analysis of oxidized rat GPx4 complies with the predicted structure, an 8-membered ring, in which selenium is bound as selenenylamide to the protein backbone. The intermediate can be re-integrated into the canonical GPx cycle by glutathione, whereas, under denaturing conditions, its selenium moiety undergoes β-cleavage with formation of a dehydro-alanine residue. The selenenylamide bypass prevents destruction of the redox center due to over-oxidation of the selenium or its elimination and likely allows fine-tuning of GPx activity or alternate substrate reactions for regulatory purposes. [ABSTRACT FROM AUTHOR]

Bringing “N” into the game: The direct chemoselective nitrogenation of unactivated alkenes can be achieved through oxidative selenium catalysis (see scheme). This method provides a broad variety of allylic imides in yields of up to 89 % using N‐fluorobenzenesulfonimide (NFSI) as the terminal oxidant and nitrogen source. Furthermore, an unprecedented selenium‐catalyzed vinylic C(sp2)–H nitrogenation was discovered. [ABSTRACT FROM AUTHOR]

The article presents information on the formation of pyridinium salts in an organoselenium-catalyzed regioselective of alkenes.

A suitable oxidative system is crucial to electrophilic selenium catalysis (ESC). This short review offers the overview of recent development in ESC with electrophilic N-F reagents as the oxidants. Several highly selective transformations of alkenes such as allylic or vinylic imidation, pyridination, syn -dichlorination, oxidative cyclization and asymmetric cyclization have been described., Competing Interests: The authors declare no conflict of interest.