One-pot Cu-catalyzed tandem aerobic oxidative cyclization for the synthesis of quinolines from 2-vinylanilines/2-arylanilines and 2-methylquinolines via C(sp3)–H/C(sp2)–H bond functionalization has been developed. Dioxygen as an ideal oxidant has been employed for this transformation. The substrates bearing various functional groups perform well in this process and generate the desired products in moderate to good yields.

A straightforward Fe-catalyzed method for the synthesis of pyrrolo[1,2-a]quinoxalines from 1-(2-aminophenyl)pyrroles and cyclic ethers, which includes functionalization of C(sp3)-H bonds and the construction of C–C and C–N bonds, has been developed. The features of this reaction are Fe catalysis, low-cost and readily accessible starting materials. Moreover, this procedure exhibits good functional group tolerance and a series of pyrrolo[1,2-a]quinoxaline derivatives are obtained in moderate to good yields.

AbstractA metal-free radical addition method for the synthesis of β-arylsulfonyl naphthalenes with homopropargylic alcohols and sulfonyl hydrazides has been developed. In this reaction, sulfonyl hydrazide is employed as the source of sulfonyl radical to produce the desired sulfone directly. There is the first example for homopropargylic alcohol through direct intramolecular addition of vinyl radical to arenes with sulfonyl radical, which is initiated by the TBAI/K2S2O8 reaction system and generates the desired products in moderate yields.

A green method to synthesize cinnolines by 6π electrocyclic reaction with alkenyl amines and TBN has been developed. TBN plays a dual role both as a nitrogen atom source and an oxidant in this procedure. Relevant mechanism experiments reveal that the reaction proceeds through electrocyclic reaction and with diazo hydroxide as a key intermediate.

A sulfenylation/cyclization reaction has been developed for the synthesis of sulfanylfurans in the presence of iodine. These processes provide facile strategies to construct C–S/O bonds, and expand the methods of synthesizing sulfanylfurans. In this transformation, various groups on homopropargylic alcohols and sulfonyl hydrazides react smoothly and the desired sulfanylfurans are obtained in moderate to good yields.

A straightforward method for synthesizing the pyrazole N-oxides from N-propargylamines and AgNO2 through oxidation/cyclization reaction had been developed. AgNO2 was used as the NO source for the first time to synthesize pyrazole N-oxides. Various substituted groups on N-propargylamines proceeded smoothly, and the desired products were obtained in good yields.

A conversion of pyridines and enamides for the synthesis of 3-bromo-imidazo[1,2-a]pyridines was developed by copper-mediated aerobic oxidative coupling in a one-pot manner. This procedure tolerates various functional groups and affords a series of 3-bromo-imidazo[1,2-a]pyridines under mild conditions.

A novel iodine-mediated oxidative tandem cyclization reaction of simple enaminones has been developed for the synthesis of substituted furopyridines through C–C/C–N/C–O bond formation in a one-pot procedure. Substituted furopyridines are obtained in moderate to good yield. In addition, I- and Br-substituted furopyridines have been successfully produced by the electrophilic substitution of N-iodo- or N-bromosuccinimide.

A novel I2-catalyzed intermolecular oxidative tandem cyclization reaction of aromatic/aliphatic olefins and α-picoline derivatives has been achieved for the synthesis of indolizines under metal-free conditions. In this transformation, substituted indolizines are obtained in moderate to good yields through C–C/C–N bond formation in one pot.

A metal-free and efficient method for the synthesis of substituted pyridines with aldehydes and NH4OAc under mild conditions using air as the oxidant was developed. This oxidative cyclization process involves direct C–H bond functionalization, C–C/C–N bond formation and C–C bond cleavage.

A direct method for the synthesis of 1,3,4-triarylpyrroles was achieved easily from cyclization of α-amino carbonyl compounds and aldehydes catalyzed by I2. Various substituted groups can be employed, and this reaction can proceed smoothly in moderate to good yields.

A direct method for the synthesis of substituted indolizines by means of I2-mediated oxidative tandem cyclization via C–N/C–C bond formation was developed. Various substituted aromatic/aliphatic enolizable aldehydes and 2-pyridylacetates/acetonitrile/acetone proceeded smoothly in this transformation, and the desired products were generated in moderate to good yields.

A direct method has been developed for iodine-mediated thiolation of naphthols/naphthylamines and arylsulfonyl hydrazides through the formation of C–S bond and cleavage of S–N/S–O bonds. In this transformation, a range of valuable thioethers are easily achieved in moderate to good yields.

An efficient method for the direct synthesis of substituted quinolines from anilines and aldehydes through C–H functionalization, C–C/C–N bond formation, and C–C bond cleavage has been developed. The method is simple and practical and employs air as an oxidant.

A Pd-catalyzed method for the synthesis of benzisoxazolones from benzohydroxamic acids using Oxone as an oxidant in a one-pot procedure has been developed. In this process, the reaction appears to be suitable for construction of various benzisoxazolones.

A copper-catalyzed method for the synthesis of imidazo[1,2-a]pyridines with aminopyridines and nitroolefins using air as oxidation agent in a one-pot procedure has been developed. In this process, the reaction appears to be very general and suitable for construction of a variety of imidazo[1,2-a]pyridines.

A sulfenylation/cyclization reaction has been developed for the synthesis of sulfanylfurans in the presence of iodine. These processes provide facile strategies to construct C–S/O bonds, and expand the methods of synthesizing sulfanylfurans. In this transformation, various groups on homopropargylic alcohols and sulfonyl hydrazides react smoothly and the desired sulfanylfurans are obtained in moderate to good yields.

A novel iodine-mediated oxidative tandem cyclization reaction of simple enaminones has been developed for the synthesis of substituted furopyridines through C–C/C–N/C–O bond formation in a one-pot procedure. Substituted furopyridines are obtained in moderate to good yield. In addition, I- and Br-substituted furopyridines have been successfully produced by the electrophilic substitution of N-iodo- or N-bromosuccinimide.

A green method to synthesize cinnolines by 6π electrocyclic reaction with alkenyl amines and TBN has been developed. TBN plays a dual role both as a nitrogen atom source and an oxidant in this procedure. Relevant mechanism experiments reveal that the reaction proceeds through electrocyclic reaction and with diazo hydroxide as a key intermediate.