Fuhong Xiao

Iodine-catalyzed regioselective 2-sulfonylation of indoles with sodium sulfinates.

Iodine-catalyzed selective 2-arylsulfonyl indole formation from indoles and sodium sulfinates is disclosed. Various substituted 2-arylsulfonyl indoles were obtained in one pot in the absence of metal catalyst at room temperature under air.

Palladium-catalyzed desulfitative cross-coupling reaction of sodium sulfinates with benzyl chlorides.

A palladium-catalyzed approach for the synthesis of diarylmethanes from sodium sulfinates and benzyl chlorides is described. Various aromatic sodium sulfinates were used as aryl sources via extrusion of SO2 and gave the diarylmethanes in moderate to good yields.

Internal Oxidant-Triggered Aerobic Oxygenation and Cyclization of Indoles under Copper Catalysis

A concise synthesis of pyrazolo[1,5-a]indole derivatives by copper-catalyzed aerobic oxygenation and cyclization of indoles with oxime acetates is described. This protocol represents an elegant example of N-1, C-2, and C-3 tri-functionalization of indoles in one-pot. Mechanistic studies indicate the reaction proceeds through a radical procedure. Oximes as an internal oxidant have been demonstrated to be a driver to initiate aerobic oxidation, which provides a new oxidative pattern for C-H functionalization even with high atom- and step-economy.

Peroxide-mediated transition-metal-free direct amidation of alcohols with nitroarenes.

An unusual direct amidation of alcohols with nitroarenes mediated by peroxides has been discovered. The reaction tolerated a wide range of functionalities, and various aromatic amides were obtained in moderate to good yields in the absence of transition-metal catalyst. The peroxides and solvents had a significant impact on the reaction yield.

Chemoselective cross-coupling reaction of sodium sulfinates with phenols under aqueous conditions

An efficient procedure for the formation of C–S bonds via direct C–H functionalization has been developed under aqueous conditions. In this process, stable and readily available sodium sulfinates were used as the sulfur source to provide aryl sulfides and sulfones in good to excellent yields. A broad range of functional groups were well tolerated in this reaction system.

Iron-Catalyzed One-Pot 2,3-Diarylquinazolinone Formation from 2-Nitrobenzamides and Alcohols

A novel approach for the synthesis of 2,3-diarylquinazolinones using iron as catalyst is described. Various 2-nitro-N-arylbenzamides reacted with benzylic alcohols to selectively give the corresponding products in the absence of external oxidant or reductant.

Four-Component Approach to N-Substituted Phenothiazines under Transition-Metal-Free Conditions

An efficient synthesis of N-substituted phenothiazines has been developed from readily available amines, cyclohexanones, and elemental sulfur. The combination use of KI/DMSO in an oxygen atmosphere significantly improved the reaction yields.

Iodine-promoted 2-arylsulfanylphenol formation using cyclohexanones as phenol source

A novel method for the formation of 2-arylsulfanylphenols using cyclohexanones as phenol source via dehydrogenation is described. Various aromatic sodium sulfinates and sulfonyl chlorides acted as efficient coupling partners to construct new C–S bonds in the presence of an iodine promoter.

Assembly of 2-Arylbenzothiazoles through Three-Component Oxidative Annulation under Transition-Metal-Free Conditions

Highly efficient methods for the synthesis of 2-arylbenzothiazoles and 2-arylnaphtho[2,1-d]thiazoles have been developed. Readily available aromatic amines, benzaldehydes, and elemental sulfur were directly assembled through oxidative annulation and C-H functionalization under transition-metal-free conditions, where DMSO or oxygen served as the oxidant. NH4I or KI as the catalyst was found to be effective to promote the transformations to give the annulation products in good to excellent yields with wide functional group tolerance.

Solvent-controlled highly regio-selective thieno[2,3-b]indole formation under metal-free conditions

An efficient three-component thieno[2,3-b]indole formation method was developed under metal-free conditions. The cascade cyclization was enabled by acid-promoted annulation of indoles, ketones and sulfur powder, which enabled modular synthesis of 2-substituted and 3-substituted thieno[2,3-b]indoles with excellent regioselectivity and broad functional group tolerance. DMF solvent played an important role in the regioselectivity control.