Visible-Light-Induced C2 Alkylation of Pyridine <i>N</i>‑Oxides

A photoredox catalytic method has been developed for the direct C2 alkylation of pyridine <i>N</i>-oxides. This reaction is compatible with a range of synthetically relevant functional groups for providing efficient synthesis of a variety of C2-alkylated pyridine <i>N</i>-oxides under mild conditions. Mechanistic studies are consistent with the generation of a radical intermediate along the reaction pathway

Visible-Light-Promoted C–H Arylation by Merging Palladium Catalysis with Organic Photoredox Catalysis

The use of a dual palladium/organic photoredox catalytic system enables the directed arylation of arenes with aryldiazonium salts with a broad substrate scope at room temperature under mild reaction conditions. This study thus serves as not only an alternative route for the biaryl motifs but also a new example for the application of an organic photoredox catalyst

Catalyst-Free Singlet Oxygen-Promoted Decarboxylative Amidation of α‑Keto Acids with Free Amines

A novel catalyst-free decarboxylative amidation of α-keto acids with amines under mild conditions has been developed. Advantages of the new protocol include avoidance of metal catalysts and high levels of functional group tolerance. In addition, the reaction can be scaled up and shows high chemoselectivity. Preliminary mechanistic studies suggest that singlet oxygen, generated from oxygen under irradiation, is the key promoter for this catalyst-free transformation

Copper-Promoted Reductive Coupling of Aryl Iodides with 1,1,1-Trifluoro-2-iodoethane

An efficient Cu-promoted reductive coupling of aryl iodides with 1,1,1-trifluoro-2-iodoethane has been developed. This reaction could occur in good yields under milder conditions as compared with previous studies. The reaction tolerated nitro, formyl, ester, ether, carbonyl, sulfonyl, and even azo groups

AIBN-Catalyzed Oxidative Cleavage of <i>gem</i>-Disubstituted Alkenes with O₂ as an Oxidant

A 2,2-azobis­(isobutyronitrile) (AIBN) catalyzed oxidative cleavage of <i>gem</i>-disubstituted alkenes with molecular oxygen as the oxidant has been described. Carbonyl compounds were obtained as the desired products in high yield under mild conditions. Based on previous documents and current experimental results, a relatively reasonable mechanism is proposed

Copper-Catalyzed Cross-Coupling Reaction of Allyl Boron Ester with 1°/2°/3°-Halogenated Alkanes

The cross-coupling reaction of allyl boron ester with 1°/2°/3°-halogenated alkanes in the presence of copper has been developed for the first time, which provides a mild and efficient method for the construction of saturated C­(sp³)–C­(sp³) bonds. This protocol shows excellent compatibility with the nonactivated primary, secondary, and even tertiary halogenated alkanes under mild conditions

Silver-Mediated Decarboxylative C–S Cross-Coupling of Aliphatic Carboxylic Acids under Mild Conditions

A silver-mediated decarboxylative C–S cross-coupling reaction of aliphatic carboxylic acid is described. This reaction occurs smoothly under mild conditions and shows good tolerance of functional groups. It provides an alternative approach for the synthesis of alkyl aryl sulfides

Cu(II)-Mediated Decarboxylative Trifluoromethylthiolation of α,β-Unsaturated Carboxylic Acids

A tunable method for the direct trifluoromethylthiolation of α,β-unsaturated carboxylic acids was developed to afford trifluoromethylthiolated ketones or alkenes. The reaction proceeds smoothly under mild conditions and shows an excellent functional group tolerance

Visible-Light-Enabled Decarboxylative Mono- and Difluoromethylation of Cinnamic Acids under Metal-Free Conditions

Several new mono- and difluoromethylation reactions of cinnamic acids using an Eosin Y catalytic system are reported. An efficient alkene fluoromethylation of α,β-unsaturated carboxylic acids was accomplished under ambient temperature and metal-free conditions, with a wide range of functional group tolerance. A mechanism that involves a radical process is proposed for this reaction

Copper-Promoted Sandmeyer Trifluoromethylation Reaction

A copper-promoted trifluoromethylation reaction of aromatic amines is described. This transformation proceeds smoothly under mild conditions and exhibits good tolerance of many synthetically relevant functional groups. It provides an alternative approach for the synthesis of trifluoromethylated arenes and heteroarenes. It also constitutes a new example of the Sandmeyer reaction