Transition-metal Catalyzed Or Promoted Organic Reactions

Transition-metal-catalyzed organic reactions for the formation of carbon–heteroatom and carbon–carbon bonds form the basis of essential and powerful strategies for the preparation of important compounds in pharmaceutical, biological, and materials sciences. Iron salts have emerged as alternative and promising catalysts for many organic transformations due to the properties of readily availability, low cost, and environmentally benign, in combination with the exceptionally high reaction rates observed and mild reaction conditions. We envisaged the application of iron catalysts in the reactions of the formation of carbon–heteroatom and carbon–carbon bonds, and we also developed other transition-metal catalyzed organic reactions in high efficiency.(1) C-Se and C-Te cross-coupling of arylboronic acids with diselenides and ditellurides have been catalyzed by iron, indium without any ligand and additive in the air. The method yields the corresponding unsymmetrical diorgano monoselenides and tellurides in good to excellent yields, displays a broad substrate scope, and is simple, convenient, effective, economical and environmentally friendly.(2) A novel and efficient synthetic methodology for the iron-catalyzed preparation of selenoesters from diselenides with acyl chlorides and acid anhydrides has been developed. In the presence of magnesium dust, Fe-catalyzed cleavage of Se-Se bonds in diselenides and then reacted smoothly with acyl chlorides and acid anhydrides respectively to generate the corresponding selenoesters in good yields. The reaction could be carried out under neutral reaction conditions and the method is simple, efficient and practical.(3) A convenient, effective, mild and simple strategy was developed for the synthesis of alkenyl halides through the intermolecular addition of benzylic alcohols to aromatic alkynes. The reactions were carried out in the presence of iron(III) bromide or chloride in 1,2-dibromoethane without additive in the air at room temperature, and the highly regio- and stereoselective (E/Z up to 99:1) alkenyl bromides and chlorides were obtained in good to excellent yields in 0.5?1 h under mild reaction conditions.(4) An effective, convenient and mild coupling reaction of benzylic alcohols with terminal alkynes has been developed. As an effective Lewis acid, Cu(OTf)₂-catalyzed arylmethylation of terminal alkynes with benzylic alcohols underwent smoothly to generate the corresponding products in BrCH2CH2Br with good yields in the absence of any base, acid, ligand and additive.