Studies On Transition-metal-catalyzed C-F,C-H Functionalization Abstract

1.Study on Dehydrofluorination of Bismuth Difluoroolefins Catalyzed by CopperFluorine-substituted olefins are are commonly occurring structural motifs which are not only used as powerful intermediates for synthesis of fluorine containing compounds,but also widely found in medicines,agrochemicals and materials.Moreover,the terminal fluoro-olefin group is a useful functionality in the design of mechanism-based enzyme inhibitors.Since the potency of these inhibitors often depends on the geometry of the olefins,their Z/E stereoisomers often exhibit different bioactivities.Most methods reported so far produce mixtures of E and Z isomers,which are often difficult to separate.Although some stereoselective methods have been developed,most of them mainly generate the E-fluoroalkenes.We have successfully developed a Z-type with high selectivity,high efficiency and wide substrate compatibility with copper as a catalyst and water as a proton source under mild conditions by C-F bond activation to synthesize Z-fluoroalkenes.2.Study on the mechanism of Dehydrofluorination of Bismuth Difluoroolefins Catalyzed by CopperWe used copper as a catalyst and water as a proton source to achieve defluorination and hydrogenation to synthesize Z-type fluoroolefins.Through the research and exploration of the reaction,we found:(1)water as the sole source of the hydrogen atom in the product.(2)ruled out the CuH-catalyzed process.(3)Z-fluorinated vinylboronate esters should be visible intermediates in reactions.(4)CuF is likely to be formed during C-F cleavage process which could transfer the boronate esters to Z-fluoroalkenes.Based on the experimental results and related experimental literature,we propose a possible reaction mechanism.3.Indole C7-deuterated methylation by Rhodium CatalysisAs a heteroaromatic scafiold frequently found in natural products,pharmaceuticals,and biologically active compounds,indole nuclei-containing structures have garnered tremendous attention over the past century,and the functional grouping of the oxime ring region is a difficult point in research.We have successfully developed a indole C7-deuterated methylation via a ruthenium-catalyzed phosphine.The method uses[Rh(cod)Cl]2 as a catalyst and KH2PO4 as a base.Under the action of no additional ligand and oxidant,deuterated acetic anhydride is used as the deuterated methyl source in the N-PtBu2 chelation-assisted group.The reaction is highly selective,highly efficient,and has a wide substrate compatibility to achieve indole C7-deuterated methylation.