TFA-promoted (hetero)arylation/hydroxylation of quinoxaline-2-one derivatives with electron-rich aromatic compounds.

A metal- and solvent-free, one-pot and TFA-promoted method for the construction of hetero/aryl-substituted quinoxalin-2-ones, pyrazin-2(1)-ones, and pyrimidin-4(3)-ones is reported. This method involves the reaction of chloro-derivatives of nitrogen heterocycles with electron-rich arenes/heteroarenes, followed by hydroxylation. This protocol is easy to use, providing access to (hetero)aryl-substituted -heterocycles in good yields.

Pd-catalyzed homo-coupling of benzofurans: one-pot synthesis of diverse 3,3'-bisbenzofurans.

An efficient and one-pot synthesis of 3,3'-bisbenzofuran derivatives has been developed. The protocol involved the use of a Pd catalyst and Cu(OAc) along with molecular oxygen as the oxidant to afford bisbenzofurans a dehydrogenative homo-coupling reaction. The reaction exhibited good functional group/heterocycle tolerance and is amenable for gram scale synthesis.

Synthesis of fused bis-indazoles/indazoles a one-pot sequential strategy.

We report here an efficient synthesis of fused bis-indazoles/indazoles a one-pot sequential strategy starting from -azido aldehydes and amines. This novel method involves the sequential formation of 2-indazole followed by a Pd-catalyzed intramolecular cross-dehydrogenative coupling reaction. Overall, this one-pot sequential reaction involved the formation of new five bonds, resulting in the formation of three heterocyclic rings.

Bimetallic Cu/Pd-catalyzed three-component azide-alkyne cycloaddition/isocyanide insertion: synthesis of fully decorated tricyclic triazoles.

The construction of fully decorated 1,2,3-triazole-fused 5-, 6- and 7-membered rings has been disclosed via a bimetallic relay-catalyzed cascade process combining azide-alkyne cycloaddition, C(sp2)-H functionalization of intermediary 1,2,3-triazoles and isocyanide insertion. The salient features of this methodology include simple starting materials, reduced synthetic steps, good substrate scope and high efficiency.