Cu/Fe-mediated Cross-Dehydrogenative-Coupling Reaction For The C(sp~2)-C(sp~3)and C(sp~3)-C(sp~3) Bond Formation

Transition-metal-catalyzed C-H bond activation has been widely employed in synthesis of modified natural products,medicine,industrial products and functional materials,and has been being one of the 'spotlighted' field of organic catalysis research.However,most of these synthetic studies generate the desired products using the pre-functionalized starting material,which would extremely increase the reaction cost and limit the scope of applications but successfully get a huge social and economic benefits.The cross-dehydrogenative-coupling(CDC)reaction has developed rapidly in recent years which can bind two C-H bonds directly to form new C-C bonds under the oxidizing agent without pre-functionalized.It has helped to synthesis expected complex molecules simpler and more efficient.In this thesis,the new C-C bond construction via low-cost transition-metal Fe/Cu catalyzed CDC reaction is studied,and a series of important compounds have been synthesized.The main obtained results are shown as bellows:1.Copper-Catalyzed Cross-Dehydrogenative-Coupling(CDC)of Coumarins with Cyclic Ethers and CycloalkanesCu-catalyzed CDC reactions of coumarins with cyclic ethers and cycloalkanes were achieved to afford a variety of C3 functionalized coumarins bearing the C(sp2)-C(sp3)bond in moderate to excellent yields.The conversion was proposed to proceed via a radical process(Scheme 1).2.Copper-mediated alkylation of furan and thiophe ne derivatives with cyclic ethersAn efficient and complementary copper-catalyzed alkylation of (benzo)furans/(benzo)thiophenes with cyclic ethers was reported.A broad range of C2 heteroaryl-substituted cyclic ethers were obtained in moderate to good yields.The results of control experiments indicated that this transformation might proceed via a radical process(Scheme 2).3.Method for Direct Synthesis of ?-Cyanomethyl-?-dicarbonyl Compounds with Acetonitrile and 1,3-DicarbonylsA novel and efficient method for the synthesis of ?-cyanomethyl-?-dicarbonyls in moderate to excellent yields using inactive CH3 CN and simple 1,3-dicarbonyls was developed(Scheme 3).A radical mechanism is proposed under the ESIMS(electrospray ionization mass spectrometry)analysis.