An ebselen like catalyst with enhanced GPx activity via a selenol intermediate

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KO^<i>t</i>Bu-Mediated Synthesis of Dimethylisoindolin-1-ones and Dimethyl-5-phenylisoindolin-1-ones: Selective C–C Coupling of an Unreactive Tertiary sp³ C–H Bond

A new reaction for the synthesis of dimethylisoindolinones has been presented from 2-halo-<i>N</i>-isopropyl-<i>N</i>-alkylbenzamide substrates and KO^<i>t</i>Bu by the selective C–C coupling of an unreactive tertiary sp³ C–H bond. The reaction manifested an excellent selectivity toward a tertiary sp³ C–H bond over primary or <i>sec</i> C–H bond. Moreover, biaryl C–C coupling along with alkyl–aryl C–C coupling can be achieved in one pot using dihalobenzamides for the synthesis of biaryl 5-phenylisoindolin-1-ones. It seems that the reaction proceeds via a radical pathway in which the aryl radical translocates via 1,5-hydrogen atom transfer (HAT), forming a tertiary alkyl carbon-centered radical. The generated tertiary alkyl radical could attack the benzamide ring in a 5-<i>exo</i>/<i>endo</i>-trig manner followed by the release of an electron and a proton, leading to a five-membered isoindolinone ring. HAT seems to be responsible for the selective functionalization of the tertiary alkyl group over primary and secondary C–H bonds

KO^<i>t</i>Bu-Mediated Synthesis of Dimethylisoindolin-1-ones and Dimethyl-5-phenylisoindolin-1-ones: Selective C–C Coupling of an Unreactive Tertiary sp³ C–H Bond

A new reaction for the synthesis of dimethylisoindolinones has been presented from 2-halo-<i>N</i>-isopropyl-<i>N</i>-alkylbenzamide substrates and KO^<i>t</i>Bu by the selective C–C coupling of an unreactive tertiary sp³ C–H bond. The reaction manifested an excellent selectivity toward a tertiary sp³ C–H bond over primary or <i>sec</i> C–H bond. Moreover, biaryl C–C coupling along with alkyl–aryl C–C coupling can be achieved in one pot using dihalobenzamides for the synthesis of biaryl 5-phenylisoindolin-1-ones. It seems that the reaction proceeds via a radical pathway in which the aryl radical translocates via 1,5-hydrogen atom transfer (HAT), forming a tertiary alkyl carbon-centered radical. The generated tertiary alkyl radical could attack the benzamide ring in a 5-<i>exo</i>/<i>endo</i>-trig manner followed by the release of an electron and a proton, leading to a five-membered isoindolinone ring. HAT seems to be responsible for the selective functionalization of the tertiary alkyl group over primary and secondary C–H bonds

KO^<i>t</i>Bu Mediated Synthesis of Phenanthridinones and Dibenzoazepinones

Synthesis of substituted phenanthridinones and dibenzoazepinones has been realized from 2-halo-benzamides in the presence of potassium <i>tert</i>-butoxide and a catalytic amount of 1,10-phenanthroline or AIBN. This new carbon–carbon bond forming reaction gives direct access to various biaryl lactams containing six- and seven-membered rings chemoselectively. Carbon–carbon coupling seems to proceed by the generation of a radical in the amide ring which leads to C–H arylation of aniline

Transition-Metal-Free Synthesis of Unsymmetrical Diaryl Chalcogenides from Arenes and Diaryl Dichalcogenides

A transition-metal-free synthetic method has been developed for the synthesis of unsymmetrical diaryl chalcogenides (S, Se, and Te) from diaryl dichalcogenides and arenes under oxidative conditions by using potassium persulfate at room temperature. Variously substituted arenes such as anisole, thioanisole, diphenyl ether, phenol, naphthol, di- and trimethoxy benzenes, xylene, mesitylene, <i>N</i>,<i>N</i>-dimethylaniline, bromine-substituted arenes, naphthalene, and diaryl dichalcogenides underwent carbon–chalcogen bond-forming reaction to give unsymmetrical diaryl chalcogenides in trifluoroacetic acid. To understand the mechanistic part of the reaction, a detailed <i>in situ</i> characterization of the intermediates has been carried out by ⁷⁷Se NMR spectroscopy by using diphenyl diselenide as the substrate. ⁷⁷Se NMR study suggests that electrophilic species ArE⁺ is generated by the reaction of diaryl dichalcogenide with persulfate in trifluoroacetic acid. The electrophilic attack of arylchalcogenium ion on the arene may be responsible for the formation of the aryl–chalcogen bond

Transition-Metal-Free Synthesis of Unsymmetrical Diaryl Chalcogenides from Arenes and Diaryl Dichalcogenides

A transition-metal-free synthetic method has been developed for the synthesis of unsymmetrical diaryl chalcogenides (S, Se, and Te) from diaryl dichalcogenides and arenes under oxidative conditions by using potassium persulfate at room temperature. Variously substituted arenes such as anisole, thioanisole, diphenyl ether, phenol, naphthol, di- and trimethoxy benzenes, xylene, mesitylene, <i>N</i>,<i>N</i>-dimethylaniline, bromine-substituted arenes, naphthalene, and diaryl dichalcogenides underwent carbon–chalcogen bond-forming reaction to give unsymmetrical diaryl chalcogenides in trifluoroacetic acid. To understand the mechanistic part of the reaction, a detailed <i>in situ</i> characterization of the intermediates has been carried out by ⁷⁷Se NMR spectroscopy by using diphenyl diselenide as the substrate. ⁷⁷Se NMR study suggests that electrophilic species ArE⁺ is generated by the reaction of diaryl dichalcogenide with persulfate in trifluoroacetic acid. The electrophilic attack of arylchalcogenium ion on the arene may be responsible for the formation of the aryl–chalcogen bond