Z-selective radical difunctionalization of aromatic alkynes: synthesis of multi-substituted triarylethenes.

An efficient method for the radical difunctionalization of aromatic alkynes has been developed, resulting in the synthesis of a range of valuable triarylethenes. This approach utilizes strategically designed aryldiazonium salts with tertiary alcohol substitution as bifunctional reagents, along with cost-effective cuprous chloride as a catalyst. The method demonstrates remarkable Z-selectivity and is capable of gram-scale preparation. Additionally, a novel spin-trapping reagent has been developed based on the synthesized product.

Photocatalytic intermolecular carboarylation of alkenes by selective C-O bond cleavage of diarylethers.

Disclosed herein is a novel radical-mediated intermolecular carboarylation of alkenes by cleaving inert C-O bonds. The strategically designed arylbenzothiazolylether diazonium salts are harnessed as dual-function reagents. A vast array of alkenes are proven to be suitable substrates. The benzothiazolyl moiety in the products serves as the formyl precursor, and the OH residue provides the cross-coupling site for further product elaboration, indicating the robust transformability of the products.

Radical-Mediated Distal Ipso-Migration of O/S-Containing Heteroaryls and DFT Studies for Migratory Aptitude.

Herein we describe an efficient distal ipso-migration of O- and S-containing heteroaryls and the radical heteroarylation of unactivated alkenes. The migration is triggered by various fluoroalkyl radicals, leading to valuable multifunctionalized ketones. The comparisons of migratory aptitude for O-/S-containing heteroaryls are comprehensively investigated. The origin of the chemoselective migration could be partially attributed to the discrepancy in the energy level of the LUMO of each heteroaryl group.

Intramolecular nitration-aminocarbonylation of unactivated olefins: metal-free synthesis of γ-lactams.

Disclosed herein is a novel, metal-free synthesis of γ-lactams through the radical-mediated nitration-aminocarbonylation of unactivated olefins. The reaction is initiated by a nitro radical generated from the homolysis of tert-butyl nitrite. The intramolecular cyanamide serves as the aminocarbonylating reagent. This protocol offers an environment-benign method to produce the synthetically valuable nitromethyl substituted γ-lactams.

Visible-light-induced consecutive C-C bond fragmentation and formation for the synthesis of elusive unsymmetric 1,8-dicarbonyl compounds.

Synthesis of the valuable unsymmetric 1,8-dicarbonyl compounds remains underexplored currently. Herein, we disclose a new strategy for the synthesis of 1,8-diketones through the coupling of cyclopropanols and cyanohydrins under visible-light irradiation. The protocol features a cascade of intriguing ring opening of cyclopropanols and remote cyano migration. The unfavorable addition of an alkyl radical to an electron-rich alkene is facilitated by the intramolecular cyanohydrin interception. A variety of multiply functionalized 1,8-diketones are furnished in useful yields. The products could be further transformed into other valuable compounds, manifesting the utility of this method.

Metal-free alcohol-directed regioselective heteroarylation of remote unactivated C(sp3)-H bonds.

Construction of C-C bonds via alkoxy radical-mediated remote C(sp3)-H functionalization is largely unexplored, as it is a formidable challenge to directly generate alkoxy radicals from alcohols due to the high bond dissociation energy (BDE) of O-H bonds. Disclosed herein is a practical and elusive metal-free alcohol-directed heteroarylation of remote unactivated C(sp3)-H bonds. Phenyliodine bis(trifluoroacetate) (PIFA) is used as the only reagent to enable the coupling of alcohols and heteroaryls. Alkoxy radicals are readily generated from free alcohols under the irradiation of visible light, which trigger the regioselective hydrogen-atom transfer (HAT). A wide range of functional groups are compatible with the mild reaction conditions. Two unactivated C-H bonds are cleaved and one new C-C bond is constructed during the reaction. This protocol provides an efficient strategy for the late-stage functionalization of alcohols and heteroaryls.

Cyanotrifluoromethylthiolation of unactivated dialkyl-substituted alkynes via cyano migration: synthesis of trifluoromethylthiolated acrylonitriles.

Herein a novel, elusive cyanotrifluoromethylthiolation of unactivated dialkyl-substituted alkynes is reported. Taking advantage of the intramolecular cyano migration strategy, the reaction proceeds stereoselectively to deliver E-olefinic products. A variety of tetrasubstituted trifluoromethylthiolated acrylonitriles are afforded in modest to good yields.

Difunctionalization of Styrenes with Perfluoroalkyl and tert-Butylperoxy Radicals: Room Temperature Synthesis of (1-(tert-Butylperoxy)-2-perfluoroalkyl)-ethylbenzene.

A novel strategy for the difunctionalization of styrenes was developed. This synthesis includes the use of electrophilic perfluoroalkyl and tert-butylperoxy radicals and produces (1-(tert-butylperoxy)-2-perfluoroalkyl)ethylbenzene at room temperature, which has been traditionally difficult to synthesize. With at least four radical species included in the transformation, its high chemoselectivity was extraordinary; the results were further elucidated using computational studies. The methodology also holds a good potential for application as a result of its mild reaction conditions, ease of further modification, and insensitivity to moisture and air.

A Cu-catalyzed four-component cascade reaction to construct ß-ester-γ-amino ketones.

Herein, a novel Cu-catalyzed four-component cascade reaction, which encompasses styrenes, diazo compounds, amines, and tert-butyl hydroperoxide (TBHP), was developed for the synthesis of ß-ester-γ-amino ketones. Mechanistically, this transformation was initiated by the interception of an electrophilic Cu-based carbene with nucleophilic α-aminoalkyl radicals, followed by a radical cascade process and an ionic Kornblum-DeLaMare reaction. The methodology was also distinguished by its wide substrate scope, easily available starting materials, and operational simplicity.