Visible-light Photocatalyzed Asymmetric Fluoroalkylation And Multicomponent Reactions

In recent years,with the gradual deepening of the concept of green sustainable development,visible-light photocatalysis has become an important tool for organic synthesis,and also facilitated the development of traditional free radical chemistry due to the the abundant,green and sustainable nature of sunlight.Among them,the development of asymmetric photocatalysis provides a new route for the efficient synthesis of chiral compounds.In this thesis,we mainly focuses on asymmetric photocatalysis and have realized enantioselective fluoroalkylation and multicomponent reactions.This manuscript includes the following five sections:Chapter 1: we summarized different types of asymmetric photocatalysis.By combining traditional chiral catalytic modes with visible-light photocatalysis,a series of asymmetric photocatalytic reactions through single electron transfer or energy transfer process have been realized.At present,traditional chiral catalytic modes such as chiral organocatalysis,Lewis acid catalysis,transition metal catalysis and enzyme catalysis have been successfully applied in asymmetric photocatalysis,and a series of different chiral catalytic reactions have been reported.Chapter 2: In this chapter,we developed an efficient asymmetric fluoroalkylation reaction and simple approach to monofluoroalkenes by merging visible light catalysis and chiral Lewis acid catalysis.A series of reported enantioselective fluoroalkylation reactions were summarized.We employed octahedral complex with metal chiral center as chiral Lewis acid catalyst,and achieved visible-light photocatalytic enantioselective C-H fluoroalkylation.By using different fluorine reagents,the synthesis of monofluoroalkenes could be selectively achieved.Chapter 3: Metal-free,visible-light induced enantioselective three-component dicarbofunctionalization and oxytrifluoromethylation of enamines via chiral phosphoric acid catalysis was introduced in this chapter.We first summarized the asymmetric multi-component difunctionalization of olefins via transition-metal catalysis and visible-light photocatalysis.We then developed a metal-free,visible-light mediated enantioselective dicarbofunctionalization and oxytrifluoromethylation of enamines in the present of chiral phosphoric acids.Using diverse carbon-centered radical precursors and electron-rich(hetero)aromatics and alcohols as nucleophiles,chiral chiral arylmethylamines aza-hemiacetals and γ-amino acid derivatives could be obtained with excellent enantioselectivity.Chapter 4: This chapter presented an enantioselective three-component Giese reaction catalyzed by visible light and chiral phosphoric acid.Giese reactions,as a powerful and reliable method,involves an electron-deficient olefin to form a new C-C bond with different radical intermediates.We found that there were only few examples of asymmetric multi-component Giese reactions.Based on the summary,we designed an enantioselective three-component Giese reaction between aldehydes,amines and alkenes through a dual visible light photocatalysis and chiral phosphoric acid catalysis to construct products containing remote γ-position chiral centers.Chapter 5: In this chapter,we described the visible-light induced radical1,4/3,4-hydroalkylation of electron-deficient alkenes enabled by an electron donor-acceptor complex.Photocatalysts were usually required in most visible-light photocatalysis,while EDA complexes could directly absorb visible light and triggerred the generation of radical intermediates through intermolecular electron transfer.However,electron-deficient olefin could not directly engage the formation of EDA complexes and additional substances was required.We founded thatα,β-unsaturated ketimines and coumarin derivatives can directly form EDA complexes with 4-alkyl-1,4-dihydropyridines,and the corresponding hydroalkylation products can be generated under the action of visible light.