Study On Trifluoromethylation Of Arenes And Heteroarenes Promoted By Manganese Compounds?MnO₂,MnSO₄·H₂O And MnCl₂·4H₂O?

Based on the extreme stability of C-F bond,it is one of the most important strategies for modulating the physicochemical properties of the organic chemicals by introducing trifluoromethyl(·CF3)into organic chemicals.In the view of synthetic chemistry,that the controllable design of triluoromethyl compounds is achieved via a more facile,efficient and green approach,is one of the research hotspots in organofluorine chemistry nowadays.The compounds involving manganese element with high valence are used to be oxidants or co-catalysts in the related reactions,but using them as catalysts to promote some organic synthesis reactions(such as trifluoromethylation)is seldom reported.Therefore,this thesis focuses on systematical investigation in trifluoromethylation of inert arenes and heterocyclic arenes compounds,in which the compounds involving manganese elements with different valence states act as catalysts or accelerants and CF3SO2Na is used as the fluorine source.The main conclusions of this dissertation are as follows:(1)CF3SO2Na can be efficiently oxidized to trifluoromethyl radical and S2O42-at 50 ? by using MnO2 as catalyst without any accelerants,thus promoting ultimate formation of trifluoromethyl compounds.The forward reaction is promoted by the subsequent reaction between MnO2 and S2O42-but synchronous producing MnSO4.The catalytic system presents good group tolerance in the oxidation of arenes and heterocyclic compounds containing N and S elements with electron withdrawing/donating groups,and the reaction yield is positively associated with the substituent's ability of donating electront.(2)The result that trifluoromethyl radical has been detected by ESR indicates that the reaction might be underwent a radical mechanism,which is the fundamental chemical approach for the formation of the target product involving trifluoromethyl.(3)CF3SO2Na has been catalyzed and oxidized to trifluoromethyl radical and S2O42-by MnSO4·H2O and MnCl2·4H2O,which is different from the system using MnO2 as catalyst.(4)Although the hydroxylation reaction cannot be directly and effectively promoted by MnO2,it can be successfully performed by quinone in the presence of MnO2.In this process,the role of MnO2 is as a catalyst to oxidize hydroquinone to quinone,further realizing the hydroxylation reaction.The main innovations of this dissertation are as follows:using MnO2 as catalyst,CF3SO2Na as trifluoromethyl radical source,a new system has been constructed for the trifluoromethylation reaction.And a new model mechanism of the formation of trifluoromethyl radical under MnO2 of varying chemical form has been confirmed and revealed;furthermore,in the carbonylation reaction,using gaseous CO as the source of carbonyl group,oxydehydrogenation of quinone can increase the efficiency of carbonyl reaction.