Pd-Catalyzed Coupling Reaction Of Difluoromethyl Subsititued Pyrazoles With Olefins Via C-H Bond Activation

This paper focused on the Pd-catalyzed coupling reaction of the difluoromethyl subsititued pyrazoles with olefins via C-H activation.A series of difluoromethyl containing1,3,5-trisubstituted pyrazoles were synthesized as reaction substrates with yields of70-90%by the difluoromethyl substituted β-diketones. And the reactivity of the C-H bond on C-4position of synthesized pyrazoles was researched through the reaction with olefins. Under the condition of Pd(OAc)2as Pd source, Ag2CO3as oxidant, BQ as ligand and DMF as solvent, the reaction of difluoromethyl substituted pyrazoles with olefins showed the best result.The effect on the reation yield of different substituent group on N-l and C-3in pyrazoles was also studied by the coupling reaction with olefins, and a series of coupling products were synthesized with the yields of30-80%.Also studied the trifluoromethyl substituted or difluoromethyl substituted pyrazoles coupling reaction results under the same conditions, further investigated the activity of C-H bond coupling reaction with benzoquinone and different fluorinated methyl. And parts of difluoromethyl substituted pyrazole coupling products for further derivatization.