Visible Light Induced Arylation And Trifluoromethylation Of Quinoline N-oxides

Quinoline and pyridine compounds are widely present in chiral materials and pharmaceutical molecules,and have attracted attention in organic synthesis and medicinal chemistry due to their unique intrinsic structure and pharmaceutical activities.In recent years,visible-light-induced chemical reactions have rapidly developed into a hot research field due to their unique advantages,and C-H bond functionalizations have attracted interest from chemists.In this thesis,the visible-light-induced arylation and trifluoromethylation of quinoline N-oxides were studied.And this protocol has several advantages including simple operation,mild reaction conditions and environmental friendliness,which opens up a new way for the synthesis of C2-substituted quinolines and pyridines.Under the visible light induction,C?sp²?–H arylation reaction was studied by using quinoline or pyridine N-oxide as raw material.The arylation of quinoline N-oxides was successfully achieved by the oxidation of diphenyl iodonium tetrafluoroborate with excited photocatalyst to generated aryl radicals,which reacted with quinoline or pyridine N-oxide and went further of deprotonation to produce the desired products.Under the optimal reaction conditions,15 different substituted quinoline N-oxides and 10 different substituted pyridine N-oxides were successfully arylation,which proved that the reaction had good applicability.According to the free radical trapping experiment,it was determined that the reaction went through a radical reaction pathway induced by visible light.The trifluoromethylation reactions were studied using quinoline N-oxide as raw materialss.Trifluoromethyl radical was formed from Tongi's reagent via visible light photoredox catalyst fac-Ir?ppy?₃,and the CF₃ radical reacted with quinoline N-oxide,then afforded C2 trifluoromethyl quinoline N-oxides after proton removal.The effects of photocatalyst,solvent,bases and other conditions on the reaction were explored,and the optimal conditions of the reaction were determined.15 trifluoromethyl quinoline N-oxides of were synthesized.According to the free radical trapping experiment,the reaction mechanism of oxidative quenching was proposed.