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Divergent Ritter-type Amination Via Photoredox Catalytic Multi-component Radical-polar Crossover Reactions

Posted on:2023-04-25Degree:DoctorType:Dissertation
Country:ChinaCandidate:S Q GuoFull Text:PDF
GTID:1521306782475534Subject:Chemistry
Abstract/Summary:PDF Full Text Request
Visble photocatalytic strategies have greatly expanded the scope of organic synthesis methods due to their mild conditions,ease of operation and controllable products.The development of new visible-light-catalysed multi-component reactions is in line with the concept of "green chemistry" because of the significant advantages of high step economy,good atomic economy and environmental friendliness.Using this powerful and gentle strategy to solve the existing problems of named reactions can make the classical organic reaction more efficient and green,so as to provide a safer and sustainable development path for modern organic synthesis methodology.This thesis focuses on the photoredox catalytic multi-component radical-polar crossover Ritter-type amination reactions and is divided into five main sections as follows.Chapter 1: The background of the whole thesis.It is illustrated from two aspects of visible light catalyzed multi-component reactions and the radical-polar crossover Ritter type reactions.The main research of this paper is introduced to address the problems of imperfect development,lack of variety of reaction types,single products and insufficiently green conditions in this field.Chapter 2: Photoredox catalytic four-component radical-polar crossover Ritter type imination reactions.A novel photoredox catalytic four-component radical-polar crossover Ritter type imination reaction was developed using readily available sulfonyl chlorides,olefins,acetonitrile and triazoles as raw materials.This photoredox system features high atom economy and redox economy,eliminates excess amounts of oxidants provides mild and easy-to-operate reaction conditions.On the basis of a series of mechanistic experiments and DFT calculations,a plausible mechanism for this reaction was proposed.Chapter 3: Photoredox catalytic four-component radical-polar crossover Ritter type imidation reactions.A novel photoredox catalytic four-component radical-polar crossover Ritter type imidation reaction was developed using simple materials such as carboxylic acid compounds as reaction substrates,following a critical multi-component Mumm rearrangement process.Furthermore,the synthetic utility of this Ritter reaction is further demonstrated by the late-stage modification of pharmaceutical derivatives.Chapter 4: Organophotoredox catalytic four-component radical-polar crossover cascade reactions for the stereoselective synthesis of β-amido sulfones.In response to the challenges of diastereoselective synthesis in visible light-catalyzed multi-component reactions and the many problems associated with radical Ritter-type reactions,such as dependence on metal catalysts,limited applicability of substrates and difficulty in obtaining highly diastereoselective products.A green and efficient organophotoredox catalytic four-component radical-polar crossover cascade reaction was developed for the diastereoselective synthesis of β-amido sulfones.This metal-free organophotoredox system has the outstanding advantages of high atomic economy,high step economy,high redox economy,high diastereoselectivity and ease of operation,providing a novel and reliable strategy for the multi-component diastereoselective synthesis of β-amido sulfones.Chapter 5: This chapter is the summary and outlook of the whole paper.Using photoredox catalytic multi-component cascade reactions as an efficient reaction strategy,three photoredox catalytic four-component radical-polar crossover Ritter type reactions have been developed in a divergent manner to address a series of problems with the Ritter reaction.It offers new possibilities for improving the named reactions and developing more efficient and greener methods for organic synthesis.
Keywords/Search Tags:visible light photoredox catalysis, multi-component reactions, Ritter reaction, imination, imidation, amido sulfones
PDF Full Text Request
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