Study On Photocatalytic Bifunctionalization Of Styrenes By Alkyl Radicals

Visible light is a kind of inexhaustible renewable energy,which is abundant in nature.The photocatalyst transits from the ground state to the excited state under illumination,and single electron transfer occurs between photocatalyst and substrates,which can deliver high active alkyl radicals under mild conditions.Since the 21st century,the achievements in the field of visible light catalysis have increased significantly.The combination of visible light as a"reagent"and catalyst has great potential for the development of efficient and selective chemical transformation.The combination of free radical chemistry and photochemistry has become a powerful means in modern synthetic chemistry.This paper is divided into the following three parts:Chapter ⅠIn the first part,assembly of trifluoromethyl（CF₃）in organic molecules can greatly change the lipophilicity and permeability of the molecules,which plays an important role in the fields of medicine,pesticides and materials.Trifluoromethyl widely exists in the structure of many drug molecules and liquid crystal materials.Introducing trifluoromethyl into the structure of drug can improve the ability of protein binding capacity and enhance the biological activity.Although fluoride levels are relatively high in the Earth’s crust,organic fluorinated compounds are extremely rare in nature.Therefore,the construction of organic molecular framework containing fluorine to prepare bioactive materials or other functional materials has become a research hotspot.In this paper,we summarize the recent research progress of trifluoromethylation reaction and the application of the corresponding new synthesis methods.In the second part,as one of the abundant resources,carboxylic acid is non-toxic,stable,and easy to store and treat.As a result of the shortage of fossil fuels and escalating energy demand,alternative sources of materials are increasingly important.In order to obtain high value chemicals such as drugs from biomass resources,carboxyl groups can be used as chemical and regionally selective leaving groups to construct new C-C bonds.The classical decarboxylation reaction needs to be carried out at high temperature,which greatly limits the suitability of the substrate.Since the 1960s,the continuous innovation of catalytic technology has made the reaction conditions milder,realizing the extensive application of decarboxylation in organic synthesis.In this paper,we summarize the research progress of decarboxylation in recent years.Chapter ⅡDifunctionalization of alkenes is a valuable tool for the synthesis of complicated compounds from simple precursors.Herein,a feasible method for the construction ofβ-trifluoromethyl-α-substituted alcohols under visible-light-induced metal-free conditions is described.This catalytic system exhibits mild reaction conditions and good compatibility of functional groups.Trifluoromethyl and alcohols are valuable structural motifs due to their unique biological properties,and this work shows the potential application in the realm of pharmacy and organic synthesis.Chapter ⅢA photocatalytic decarboxylative radical addition bifunctionalization cascade for the synthesis of functionalized alcohols is described.The catalytic cycle is completed through single-electron transfer.The advantages of this reaction are the commercially available materials,wide functional group compatibility,and mild conditions.Notably,some amino acids and bioactive carboxylic acids can provide corresponding products in moderate to good yields,reflecting the potential value in drug development.