An unprecedented palladium-catalyzed cyanation of aromatic C-H bonds by using tertiary amine derived isocyanide as a novel cyano source was developed. Cu(TFA)(2) was used as a requisite stoichiometric oxidant. Mechanistic studies suggest that a tertiary carbon cation-based intermediate is involved following the C-N bond breakage.

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A metal-free synthesis of diversified benzimidazoles from N-arylamidines through a phenyliodine(III) diacetate (PIDA) promoted intramolecular direct C(sp(2))-H imidation has been developed. The reaction proceeds smoothly at 0 °C or ambient temperature to provide the desired products in good to excellent yields. The synthesis of 2-alkyl- or 2-alkyl-fused benzimidazoles, which are generally inaccessible by similar Pd- or Cu-catalyzed approaches, can also be achieved.

A selective C3 carboxamidation of indoles including free (N-H) ones by palladium-catalyzed sequential C-H activation-isocyanide insertion has been developed.

An efficient synthesis of free (NH)-phenanthridinones through Pd-catalyzed C(sp(2))-H aminocarbonylation of unprotected o-arylanilines under an atmospheric pressure of CO has been developed. Some ortho heteroarene substituted anilines as well as N-alkyl protected o-arylanilines are also suitable substrates for this C-H aminocarbonylation reaction.

An efficient palladium-catalyzed enantioselective isocyanide insertion/desymmetrizing C(sp 2 )−H bond activation reaction allowed by a SPINOL-derived phosphoramidite ligand was developed. 3,4-Dihydroisoquinolines containing C3 quaternary stereogenic centers were obtained in high yields with good enantioselectivity under mild conditions.

A novel access to 2-substituted benzoimidazoles, through unprecedented denitrogenative imidoyl radical cyclization of 1-azido-2-isocyanoarenes, has been developed. This tandem radical process was initiated by adding a C- or P-centered radical to isocyanide, followed by cycloaddition of the imidoyl radical to the azido group. Then, nitrogen loss and hydrogen abstraction of the resulting aminyl radical from surroundings delivered 2-substituted benzoimidazoles. Carbon radicals generated from another annulation process could also be applied, furnishing various heterocycle linked benzoimidazole derivatives.

A metal-free synthesis of diversified pyrido[1,2-a]benzimidazoles and 1H-benzo[d]imidazoles from N-aryl-2-aminopyridines and N-arylamidines has been developed. The C-H cycloamination reaction was catalyzed by hypervalent iodine(III) species generated in situ from iodobenzene (catalytic) and peracetic acid (stoichiometric). The reaction proceeded smoothly at ambient temperature to provide the corresponding N-heterocycles in good to excellent yields.