A novel metal-free synthesis of 2-substituted benzothiazoles from easily available o-chloronitrobenzenes and benzyl chlorides using elemental sulfur as traceless oxidizing agent has been developed. The protocol provides a simple, efficient, and atom-economic way to access to benzothiazoles in moderate to excellent yields. And the approach exhibited good functional group tolerance.Download high-res image (97KB)Download full-size image

•An efficient one-pot three-component reaction.•The yield was up to 98%.•Good functional group tolerance.•Heterocycle methylene chlorides substrates were compatible for the reaction.An efficient one-pot three-component reaction of 2-iodoanilines, benzyl chlorides and elemental sulfur to form 2-substituted benzothiazoles in satisfactory yields (up to 98%) has been described. The reaction tolerated a wide range of functional groups on the aromatic ring. And heterocycle methylene chlorides substrates were also found to be compatible.Download high-res image (85KB)Download full-size image

•Pd(dppf)Cl2 has been used as an efficient catalyst for the reaction.•Benzimidazoles were synthesized in good yields with good functional group tolerance.•No additional additive, oxidant, or reductant was required for the reaction.[1,1′-Bis(diphenylphosphino)ferrocene]dichloropalladium(II) has been used as an efficient catalyst for the synthesis of 2-substituted benzimidazoles via a hydrogen-transfer strategy. Various 2-substituted benzimidazoles were synthesized in good to excellent yields (up to 97%). The reaction shows good functional group tolerance. And no additional additive, oxidant, or reductant was required for the reaction.

N-(2-Chloro-phenyl)-2-halo-benzamides (halo=I/Br/Cl) as substrates were used for the one-pot synthesis of 2-arylbenzoxazole derivatives via copper-catalyzed intermolecular C–N/intramolecular C–O couplings with primary amines. This aryl amination offers clean reaction conditions and easy work-up in good yields by using CuI as catalyst, readily available 8-hydroxyquinoline as ligand, K3PO4 as base, DMF as solvent.

A novel solvent-free and catalyst-free synthesis of benzothiazoles from 2-chloronitrobenzene, elemental sulfur, and aliphatic amine has been developed. The reaction tolerated a wide range of functionalities, and various benzothiazoles were synthesized in moderate to good yields in the absence of external oxidant or reductant.