Benzimidazol-2-ones have various biological functions and are usually prepared by reactions of substituted benzene-1,2-diamines with carbonyl-containing compounds or intramolecular N-arylations using substrates with carbon-halogen bonds. However, the starting materials of these protocols are often not readily available. Herein, a simple and practical metal-free oxidative C–H amidation of N,N′-diarylureas has been developed that takes place at room temperature. This protocol uses readily available N,N′-diarylureas as the starting materials and inexpensive PhI(OAc)₂ as the oxidant without the need of a catalyst, ligand, or the exclusion of air. The present method has a wide functional group tolerance and affords a new and practical strategy for the synthesis of N-heterocycles.

A highly efficient rhodium-catalyzed hydrosilylation of N-sulfonyl-1,2,3-triazoles has been developed. The protocol uses readily available N-sulfonyl-1,2,3-triazoles and triphenylsilane as starting materials, and the reactions first gave 2-(triphenylsilyl)-2-aryl-N-(arylsulfonyl)ethanimines, the isomerization of which provided (E)-2-(triphenylsilyl)-2-aryl-N-(arylsulfonyl)ethenamines in the presence of triethylamine; the reduction of which with LiAlH₄ led to 2-(triphenylsilyl)-2-aryl-N-(arylsulfonyl)ethanamines. It is worthwhile to note that the obtained products could be converted into indole and arylethylamine derivatives. Therefore, the highly efficient rhodium-catalyzed hydrosilylation method is a valuable strategy for synthesis of diverse compounds.

A novel, easy and useful copper-catalyzed selective acylation of secondary anilines with ethyl glyoxalate has been developed, and the corresponding indoline-2,3-dione derivatives were prepared. The procedure comprises the sequential intermolecular copper-catalyzed selective oxidative ortho-site aromatic acylation of the NH group in secondary anilines and intramolecular nucleophilic attack of the NH group to the ester. The inexpensive, easy and efficient method should provide a new strategy for synthesis of dicarbonyl compounds.

An unexpected copper-catalyzed sequential C-arylation and denitrogenation of tetrazoles leading to 1,3-diaminoisoquinoline derivatives has been developed, and the corresponding 1,3-diaminoisoquinoline derivatives were obtained in moderate to good yields. The method provides a novel strategy for the synthesis of isoquinoline derivatives containing various functional groups.

A convenient and efficient palladium-catalyzed synthesis of aromatic ketones and isoindolobenzimidazoles has been developed via selective aromatic CH bond acylation. The protocol uses palladium acetate as the catalyst, readily available carboxylic acids as the acylating reagents, trifluoroacetic anhydride as the activated agent of the acids, and the corresponding aromatic ketones and isoindolobenzimidazoles were obtained in good to excellent yields. This finding should provide a new and useful strategy for synthesis of aromatic ketones and isoindolobenzimidazoles.

A novel, efficient, and practical method for the synthesis of imidazopyridine derivatives has been developed through the copper-catalyzed aerobic oxidative CH functionalization of substituted pyridines with N-(alkylidene)-4H-1,2,4-triazol-4-amines. The procedure occurs by cleavage of the NN bond in the N-(alkylidene)-4H-1,2,4-triazol-4-amines and activation of an aryl CH bond in the substituted pyridines. This is the first example of the preparation of imidazopyridine derivatives by using pyridines as the substrates by transition-metal-catalyzed CH functionalization. This method should provide a novel and efficient strategy for the synthesis of other nitrogen heterocycles.

Efficient copper-catalyzed aerobic oxidative CH and CC functionalization of 1-[2-(arylamino)aryl]ethanones leading to acridones has been developed. The procedure involves cleavage of aromatic CH and acetyl CC bonds with intramolecular formation of a diarylketone bond. The protocol uses inexpensive Cu(O₂CCF₃)₂ as catalyst, pyridine as additive, and economical and environmentally friendly oxygen as the oxidant, and the corresponding acridones with various functional groups were obtained in moderate to good yields.

Selective functionalizations of aryl CH bonds in 2-arylpyridines have been developed via sequential borylation and aerobic oxidative copper catalysis, and the corresponding aryl halides, sulfones, azides and arylamines were obtained in good yields. The protocol uses cheap and readily available boron tribromide (BBr₃) as the borylating reagent, and inorganic salts (potassium iodide, ammonium bromide, sodium alkylsulfinates, sodium azide) as the functional group sources. This method makes functionalizations of aryl CH bonds easy.

A copper-catalyzed domino method for synthesis of isoquinolino[2,3-a]quinazolinones has been developed using readily available, substituted methyl 2-(2-haloobenzamido)benzoates and nitriles as the starting materials. The domino process comprises an Ullmann-type C-arylation, intramolecular addition of NH with CN, and nucleophilic attack of amino to ester group. The inexpensive, convenient and efficient copper-catalyzed method should provide a new and useful strategy for constructing nitrogen heterocycles.

A convenient copper-catalyzed domino method for the synthesis of benzimidazo[2,1-b]quinazolin-12(6H)-ones has been developed via reactions of readily available substituted 2-bromo-N-(2-halophenyl)benzamides with cyanamide, in which cyanamide acts as a useful building block.

A simple, efficient and practical approach to 1H-indolo[1,2-c]quinazoline derivatives has been developed that uses inexpensive and readily-available catalyst and substrates. The method should provide a new strategy for N-fused heterocycles and will show wide application in organic chemistry and medicinal chemistry.

A simple, practical, and highly efficient copper-catalyzed one-pot synthesis of imidazo/benzoimidazoquinazolinones has been developed. The procedure is based on a sequential copper-catalyzed Ullmann-type N-arylation and aerobic oxidative intramolecular CH amidation. This method should provide a new and useful strategy for construction of N-heterocycles.

An efficient copper-catalyzed method has been developed for the synthesis of poly-N-heterocycles containing amino acid residues. The protocol uses readily available 2-halobenzamides containing amino acids and their methyl esters, substituted phenylacetonitriles, and malononitrile as the starting materials and the reactions were performed well under mild conditions. The method should provide a novel and useful strategy for synthesis of N-heterocyclic compounds.

A simple and general copper-catalyzed method has been developed for transformations of various functional groups (I, N₃, SO₂R, OH, NH₂, and NO₂) on aromatic rings from arylboronic acids in water under air. The protocol uses cheap and readily available inorganic salts (KI, NaN₃, NaSO₂R, NaOH, NaNO₂) and aqueous ammonia as the functional-group sources, simple Cu₂O/NH₃ as the catalyst system, environmentally friendly water as the solvent, and oxygen in air as the oxidant. Importantly, the copper catalyst system in water was recyclable. This study should provide a useful strategy for interconversions of the functional groups on aromatic rings.

We have developed a simple and efficient copper-catalyzed method for the synthesis of 2-amino-1H-indole-3-carboxylate derivatives via cascade reactions of substituted N-(2-halophenyl)-2,2,2-trifluoroacetamide with alkyl 2-cyanoacetate or malononitrile under mild conditions, and the method is of wide practical application.

We have developed a novel and highly efficient, copper-catalyzed synthesis of internal alkynes via oxidative couplings of aromatic boronic acids with terminal alkynes at room temperature. The protocol uses inexpensive copper(I) oxide [Cu₂O] as the catalyst, oxygen in the air as the stoichiometric oxidant; no ligand and sealed reaction vessels are required, and remarkable functional group tolerability is observed with coupling occurring.

We have developed a simple and practical copper-catalyzed method for the synthesis of 1,2,4-benzothiadiazine 1,1-dioxide derivatives via cascade reactions of substituted 2-halobenzenesulfonamides with amidines, and the method is of value for the construction of this kind of molecules with biological and medicinal activities.

We have developed an efficient copper-catalyzed method for the synthesis of N-alkylanthranilic acids. The protocol uses inexpensive copper(I) iodide/racemic 1,1′-binaphthyl-2,2′-diol (rac-BINOL) as the catalyst/ligand system, readily available 2-halobenzoic acids and aliphatic amines as the starting materials, the coupling reactions were performed at room temperature, and various functionalities in the substrates were tolerated.

We have developed a general and highly efficient iron(II) chloride/N-bromosuccinimide (NBS)-mediated method for the synthesis of imides and acylsulfonamides via couplings of thioesters with carboxamides/sulfonamides, and the method is simple, economical and shows practical advantages.

We have developed a green and practical method for the Huisgen cycloaddition of water-insoluble sulfonyl azides with alkynes ‘on water’ at room temperature under catalysis of the inexpensive catalyst system CuX/PhSMe, and addition of the ligand (thioanisole) greatly inhibited cleavage of the N¹N² bond in the 5-cuprated N-sulfonyltriazole intermediates to amides and improved the yields of N-sulfonyltriazoles.

We have developed a highly efficient method for the copper-catalyzed amidation of aldehydes in the presence of N-bromosuccinimide (NBS). This method is simple, economical, and has practical advantages for synthesis of imides.