Synthesis Of Fluorine-Containing Compounds Based On Radical Addition Of Alkenes

Fluorine-containing compounds with special structures,different properties and diverse functions have been used in the fields of medicine,pesticides,and materials,which can be constructed by the free radical fluoroalkylation of alkenes.Due to the importance of the moiety,great progress has been made in transition metal catalysis and visible light-induced iridium and ruthenium catalysis for the fluoroalkylation of alkenes.However,the application and development of organofluorine chemistry are limited,due to the expensive catalysts,large dosages,low catalytic efficiency,or harsh reaction conditions.In view of these problems,we summarized rencent researches on the radical fluoroalkylation of alkenes.We have developed some a series of fluorine-containing compounds based on free radical reaction of alkenes.The main research results are summarized as following:1.A novel and atom-economic method for the catalytic synthesis of remote perfluoroalkyl-containing ketones by radical fragmentation and reconstruction of enol perfluoroalkyl sulfonates was developed.Preliminary mechanistic studies showed that oxidative fragmentation released a perfluoroalkyl radical from the perfluoroalkylsulfonyl group of enol perfluoroalkanesulfonate and subsequent addition of the perfluoroalkyl radical to another enol perfluoroalkanesulfonate to obtain remote perfluoroalkyl-containing ketones through 1,6-HAT and radical rearrangement reaction.This method utilized readily available starting materials,and is easy to handle,featureing a wide substrate scope for both aromatic and aliphatic compounds.2.An efficient visible-light-induced C-H perfluoroalkylation of quinoline-4-ols was developed in the absence of any photocatalyst.The mechanism studies shown that the photochemical active EDA complex from 4-hydroxyquinoline anion and perfluoroalkane iodide played a key role in the generation of free radical.3.An inexpensive and efficient copper-catalyzed difluoroalkylation reaction of coumarin was developed.Under copper catalysis,the cheap difluorobromide generated difluoroalkyl radicals and reacted with electron rich alkenes to form difluoroalkyl substituted coumarin at the 3-position of coumarin.4.A copper-catalyzed thiolation/trifluoromethylation reaction of alkenes with Togni I reagent and thiophenol was developed.A series of alkenes and thiophenols can be used in this reaction system.Preliminary mechanistic studies showed that the reaction involved a free radical pathway.