Cu/Fe-catalyzed cross-coupling reactions: Enroute to heterocycles

This book described the Cu/Fe catalyzed Carbon-Carbon and Carbon-Heteroatom Cross-Coupling reactions. The catalytic applications of the synthesized CuFe2O4 nanoparticles were explored for various cross-coupling reactions. Terminal alkynes underwent cross-coupling reactions with aryl iodides in presence of base and CuFe2O4 nanoparticles under ligand free conditions. N-arylation of various NH-heterocycles with differently substituted aryl halides (X = I, Br, Cl) were investigated. Catalytic efficiency of CuFe2O4 nanoparticles was further exploited for the C-S cross-coupling of aryl and alkyl thiols with aryl halides. The superparamagnetic nature of CuFe2O4 nanoparticles was found to be advantageous for their easy, quick and quantitative separation from the reaction mixture. Negligible leaching of Cu and Fe in consecutive cycles makes the catalyst economically and environmentally benign. Scope of this catalytic protocol further extended to one-pot synthesis of tricyclic dibenzothiazepines. Furthermore, an expedite Fe-catalyzed, regioselective synthesis of 1,3- and 1,3,5-substituted pyrazoles from diaryl hydrazones and vicinal diols have been described.