Nickel Catalyzed Aryl-Aryl Bridging C-N Bond Activation of 2-Pyridylpyridones and 6-Purinylpyridones

A Ni-catalyzed C-N bond activation of 2-pyridylpyridone and 1-(9-alkyl 9H-purin-6-yl)pyridin-2(1H)-one and coupling with arylboronic acid have been achieved. A unique feature of this reaction is the strategic activation of the bridging C-N bond and replacement of the pyridone unit with aryl groups using nickel catalyzed Suzuki-Miyaura coupling. This provides an exciting new tool to build C-C bonds in the place of pyridones. A wide variety of substrates and boronic acids are amenable to this transformation. More importantly, we have successfully synthesized a variety of C(6)-arylated purines via deaminative cross-coupling which are very useful in developing unnatural nucleobases, nucleotides, and nucleosides.

Visible light mediated organocatalytic dehydrogenative aza-coupling of 1,3-diones using aryldiazonium salts

An efficient protocol for diazenylation of 1,3-diones under photoredox conditions is presented herein. C-N bond forming Csp3 -H functionalization of cyclic and alkyl diones by unstable aryl diazenyl radicals is achieved through reaction with aryldiazonium tetrafluoroborates by organocatalysts under visible light irradiation. The reaction has wide substrate scope, gives excellent yields, and is also efficient in water as a green solvent. This method provides an easy access to aryldiazenyl derivatives that are useful key starting materials for the synthesis of aza heterocycles as well as potential pharmacophores.

Synthesis of ortho-arylated and alkenylated benzamides by palladium-catalyzed denitrogenative cross-coupling reactions of 1,2,3-benzotriazin-4(3H)-ones with organoboronic acids

An efficient palladium-catalyzed denitrogenative cross-coupling reaction of 1,2,3-benzotriazin-4(3H)-ones with organoboronic acids is described. The reaction affords various ortho-aryl and alkenylated benzamides in good to high yields.

Direct C-4 alkylation of quinazoline N-oxides with ethers via an oxidative cross-coupling reaction under metal-free conditions

A novel and efficient protocol for the direct C-4 alkylation of quinazoline-3-oxides via radical oxidative coupling between quinazoline 3-oxides and ethers in the presence of TBHP was developed. The reaction proceeded smoothly under metal-free conditions, which provided quinazoline-containing heterocyclic molecules in moderate to good yields.

Denitrogenative palladium-catalyzed coupling of aryl halides with arylhydrazines under mild conditions

A novel, simple, and efficient protocol via Pd(ii)-catalyzed denitrogenative coupling of arylhydrazines with aryl halides under ambient and mild conditions.

Acid-promoted denitrogenative Pd-catalyzed addition of arylhydrazines with nitriles at room temperature

Pd(TFA)₂-catalyzed denitrogenative addition proceeded with selective C–N bond cleavage of arylhydrazines with nitriles under air at room temperature.

Palladium-catalyzed Heck coupling of arylhydrazines via C–NHNH2 bond activation

A novel palladium-catalyzed Heck coupling reaction of arylhydrazines with olefins is described, which affords various styrenes with high efficiency. This transformation proceeds through a C–NHNH₂ bond activation under mild conditions.

Copper-catalyzed synthesis of aryldiazo sulfones from arylhydrazines and sulfonyl chlorides under mild conditions

A simple and effective procedure for the preparation of aryldiazo sulfones by Cu-catalyzed sulfonylation/dehydrogenation is presented.

Palladium and copper-catalyzed ligand-free coupling of phenylhydrazines in water

An efficient methodology for the synthesis of biaryls via Pd/Cu catalyzed coupling of unprotected phenylhydrazines in water is reported.