| Over the past half-century,transition metal-catalyzed cross-coupling reactions have gradually developed into the most direct and efficient strategies for the construction of carbon-carbon bonds.Today,transition metal-catalyzed cross-coupling reactions have been widely used in the synthesis of natural products,the research and development of medicines and pesticides,the production of fine chemicals,and the modification of functional materials.As a good supplement and development to the mono-transition metal catalytic system,the cooperative bimetallic catalytic reaction can complete chemical transformations that cannot be achieved by traditional catalytic systems in many cases;the development of novel and efficient cooperative catalytic modes is one of the research hotspots in transition metal-catalyzed cross-coupling reactions.This dissertation focuses on the systems of cooperative Cu/Pd catalysis,and systematically summarizes the research progress of cooperative Cu/Pd-catalyzed coupling reactions in the first chapter;through the strategies of cooperative Cu/Pd catalysis,we have realized the borylallenylation of alkynes and enynes in addition to selective decarbonylative coupling reaction of furan-2,5-dicarbonyl chloride.The specific works are as follows:Research content 1:Ene-allenes are not only important skeleton units of various natural products,but also have a wide range of uses in organic reactions as versatile building blocks;it’s significant to develop a facile and efficient method for the synthesis of ene-allenes.In the second chapter,a series of boryl-substituted ene-allenes were successfully synthesized via borylative cross-coupling with propargyl carbonate using readily available alkynes as substrates under the catalysis of IMesCuCl/Pd(dppf)Cl2.The reaction provided target products with high yields and excellent regioselectivity,a variety of functional groups were well compatible under this system.Through further transformations of boryl-substituted ene-allenes,the application value of cooperative Cu/Pd-catalyzed borylallenylation of alkynes was demonstrated.This catalytic system was also suitable for the borylallenylation of vinylarenes.Research content 2:Conjugated bisallenes are an intriguing class of compounds in allene chemistry.The unique molecular structure makes them highly active in pericyclic reactions,halogenation and oxidation reactions,etc;however,it also brings difficulties in the synthesis of conjugated bisallenes.In the third chapter,we developed a cooperative Cu/Pd-catalyzed borylallenylation of 2-trifluoromethyl-1,3-enynes with propargyl carbonates.Under mild conditions,both aryl-and alkyl-substituted enynes could be successfully converted,conjugated bisallenes with various functional groups were synthesized with high regioselectivity.The plausible reaction mechanism involves the transmetalation between allenylcopper and allenylpalladium intermediates.The allenol compounds generated from the oxidation of the boron-containing conjugated bisallenes underwent an iodocyclization reaction to afford dihydrofuran derivatives.Research content 3:As the fundamental substrate materials,alkynes undergo organic functionalization to form complex compounds which are widely used in the synthesis of natural products,medicines and functional materials.The importance of Sonogashira cross-coupling is attributed to its benefit in the effective synthesis of alkynes.Furandicarboxylic acid(FDCA),as a bio-based platform molecule,has received widespread attention for its functional transformation.In the fourth chapter,we used the carboxylic acid derivative-furandicarbonyl chloride as the starting material to achieve the alkynylation of furan ring by Cu/Pd-catalyzed decarbonylation Sonogashira coupling.In the process of research,we found that by adjusting the catalyst’s ligands and reaction temperature,the selective decarbonylation coupling reaction of furandicarbonyl chloride can be realized,thereby preparing a variety of furan-alkyne compounds. |
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