Study Of Copper Catalyzed Carbon-Hetero Cross-Coupling Reactions In PEG-400

Low molecular weight liquid polyethylene glycol （PEG） as a novel green solventfor organic reactions have been attracting great attention. They are non toxic,biodegradable, nonvolatile, nonflammable and inexpensive. Moreover, they candissolve a great range of organic compounds and organometallic complexes. Thus,PEG-400as a new reaction medium has begun to attract more attention. Thedissertation focuses on copper catalyzed carbon-hetero cross-coupling reactions usingPEG-400as reaction medium.We have developed an efficient CuI/PEG-400system for hydroxylation of arylhalides with potassium hydroxide. This protocol offers a direct transformation of aryliodides or bromides to substituted phenols in great diversity with up to96%isolatedyield. Similarly, the cross-coupling reaction between aryl halides with aqueousammonia was efficiently catalyzed in CuI/PEG-400system with up to96%yield.An efficient copper-catalyzed S-arylation of KSCN or Na₂S·9H₂O with aryl halidesin PEG-400is developed. A range of electron-withdrawing or electron-donating aryliodides and aryl bromides were found to be applicable to the environmentally benignsystem. The present procedure is mild and tolerant of a variety of functional groupswith up to98%isolated yield.We study copper catalyzed cross-coupling reactions of2-mercaptobenzothiazoleand aryl halides using PEG-400as reaction medium. With different copper sources,different coupling products were obtained with excellent selectivity. The C（aryl）-Scoupling products were obtained using CuI as copper source; while using CuO ascopper source received the corresponding C（aryl）-N coupling products, up to95%selectivity and93%yield.Finally, we study copper catalyzed cross-coupling reactions of aryl iodides andNa₂Fe（CN）₅NO·2H₂O using PEG-400as reaction medium with up to95%yield.