Application Of Selectfluor In C-S Bond Cleavage And α-C(sp~3)-H Functionalization Of Sulfide Compounds

Sulfide compounds are an important part of the human body and can be used to build proteins and enzymes.At present,there are mainly two selective conversion methods for sulfide compounds:The first is the selective construction of C-C and C-heteroatom bonds through C-S bond cleavage,The second is to construct organosulfur compounds by functionalizing the sulfur atoms of sulfide compounds withα-C(sp~3)-H bonds.Usually,the selective conversion of sulfide compounds is mainly achieved under transition metal catalysis or promotion.This synthesis strategy will inevitably lead to the residue of metal catalysts,which also greatly limits its application in biomedicine and food.Therefore,it is particularly important to explore methods for promoting the selective conversion of thioether compounds without metal participation.Selectfluor is not only an important fluorination reagent,but also can be used as transition metal oxidant,Lewis acid catalyst,F~+ion initiator,free radical initiator,and deprotection reagent to participate in organic reactions.Based on the wide application of Selectfluor as a"fluorine-free"functional reagent in organic synthesis,In this paper,Selectfluor is used as a"fluorine-free"functionalization reagent to accesssulfide compound C-S bond cleavage orα-C(sp~3)-H bond functionalization toaccess pharmacologically active dialkyl ethers and pharmacologically 2-methyl-4H-benzo[d][1,3]oxathiin-4-one derivatives.The main content includes the following three parts:The first part:Summarizes the application of Selectfluor as an electrophilic fluorination reagent and a"fluorine-free"functional reagent in the field of organic synthesis.The second part:We discovered a method of Selectfluor mediated methyl sulfide C-S bond cleavage to construct C-O bond to access dialkyl ether.This reaction uses 3-(methylthio)-N-phenylpropionamide and methanol as raw materials,and uses Selectfluor as the F~+ion initiator under alkaline conditions to achieve a higher yield in 1,4-dioxane.Synthesize a series of dialkyl ether,This method provides an important supplementary method for the synthesis of dialkyl ether compounds.The third part:We have developed a novelα-C(sp~3)-H bond functionalization reaction of aryl sulfide sulfur atoms without transition metal participation.This reaction uses 2-(ethylthio)benzoic acid as the reaction substrate and Selectfluor as the free radical initiator to obtain a series of 2-methyl-4H-benzo[d][1,3]oxathiin-4-one derivatives.This synthetic method has a wide range of substrate application and functional group tolerance,including some more reactive groups such as alkenyl,alkynyl,ester,and cyano groups.In addition,this synthetic method can also prepare 2-methyl 4H-benzo[d][1,3]oxathiin-4-one derivatives on a gram scale.