Electrochemically Promoted Copper-catalyzed Arylation Of Alkynes

The internal alkyne structure widely exists in various biologically active natural product molecules,and is also an important component unit of conjugated oligomers,polymers,dendrimers,macrocycles and optoelectronic materials.Therefore,how to expand the new synthetic methods of organic molecules with inner alkyne structure has become a research hotspot.In recent years,with the rise of electrochemistry and the development of porous organic polymer materials,they have been applied in the field of organic synthesis catalysis.Porous organic polymers(POPs),as a new generation of porous materials,are a very important class of heterogeneous supports for homogeneous catalysts.As a kind of clean energy,electric energy in electric reaction can solve the consumption of non-renewable resources in traditional organic synthesis reaction to a great extent.It has incomparable advantages over traditional organic synthesis methods.At the same time,many methods for copper-catalyzed syntheses of internal alkynes from alkynes have also been reported in the past few decades.However,these methods have more or less disadvantages such as high temperature,the use of toxic solvents,and the unrecyclability of metal catalysts.Therefore,it is particularly important to explore a new green synthesis method.In this thesis,a novel Cu/POP-Bpy heterogeneous catalyst was prepared and combined with the electric to explore a green and sustainable synthesis method of internal alkynes compounds,and successfully prepared a variety of internal alkynes products.(1)The electrochemically-promoted simple copper-catalyzed cross-coupling reaction of terminal alkynes and phenylboronic acids was investigated.After screening a series of catalysts,it was found that copper salts were deposited on the cathode,and other possible influencing factors were screened,including base,electrode,solvent,electron transfer medium and current,etc.Under the optimal reaction conditions,the target product could be produced with a yield of 77 %,but the deposition of the catalyst on the cathode could not be avoided.(2)Porous organic polymers supported copper catalyst Cu/POP-Bpy was designed and synthesized for the cross-coupling reaction of terminal alkynes and phenylboronic acid.The optimal reaction conditions were found by screening the amount of solvent,base and catalyst.And 24 internal alkyne compounds were successfully prepared.The prepared porous organic polymer catalyst Cu/POP-Bpy can effectively avoided the deposition of copper at the cathode in the electric reaction,and both aromatic and aliphatic alkynes were good substrates.We also speculated the possible mechanism of the reaction.Finally,the elemental composition and microstructure of the catalysts were characterized by BET,SEM,XPS,ICP-OES and TEM.