【作者】 王亚楠；

【导师】 蓝宇；

【作者基本信息】 郑州大学 ， 物理化学， 2022， 硕士

【摘要】 自19世纪末以来,人们一直在研究重氮化合物的合成和应用。脂肪族重氮化合物和芳基重氮盐这两种重氮化合物以其较好的反应活性广泛存在于有机合成转化中。在过去的几十年中脂肪族重氮化合物被广泛用于过渡金属催化反应中金属卡宾的前体,随着可见光催化技术的不断发展,可见光诱导脂肪族重氮化合物的转化以其绿色高效的特点引起了越来越多人的关注。与脂肪族重氮化合物不同的是,芳基重氮盐既可以发生脱去氮基团的取代反应,又可以通过保留氮基团构建其他化合物难以合成的含有偶氮、腙以及含多氮的杂环化合物。虽然该领域在实验上得到了快速的发展,但对于重氮化合物转化过程中的机理与化学选择性起源的探讨仍然欠缺。因此通过密度泛函理论对这类反应的机理进行探究具有非常重要的意义。本论文采用密度泛函理论对涉及脂肪族重氮化合物和芳基重氮盐的三个转化反应进行详细的机理探究。本论文主要分为五个章节:第一章对量子化学基础知识、本论文使用的分析方法和重氮化合物进行了简单的背景介绍,第二章到第四章分别对α-芳基重氮酯多组分偶联反应、金催化芳基重氮盐施密特型反应和金催化芳基重氮盐炔烃三官能化反应进行了详细的理论研究。以下是对第二章到第四章内容的简要描述:在第二章中我们采用密度泛函理论对可见光催化α-芳基重氮酯、胺、二氧化碳和环醚多组分偶联反应的机理和化学选择性起因进行了探究。机理研究表明可见光光解α-芳基重氮酯脱去氮气生成卡宾物种,不同醚对卡宾物种的亲核进攻得到不同氧鎓离子中间体的稳定性决定了反应的化学选择性。基于绝对定域分子轨道的能量分解分析表明,极化项和电荷转移项对不同氧鎓离子稳定性至关重要,通常局部亲核性会影响分子的极化和电荷转移,因此亲核性强的四氢呋喃倾向于得到α-芳基重氮酯、胺、二氧化碳和环醚四组分偶联的产物。第三章我们采用密度泛函理论对金催化1,3-烯炔乙酸酯与芳基重氮盐施密特型反应的机理和区域选择性成因进行了探究。机理研究表明反应首先经过Au(I)阳离子催化1,3-烯炔乙酸酯进行分子内纳扎罗夫环化反应得到环戊二烯乙酸酯,其中1,2-σ迁移过程决定了反应的区域选择性,纽曼投影式分析表明仲碳发生1,2-σ迁移会释放环张力更容易得到所需的环戊二烯乙酸酯中间体。芳基重氮盐与环戊二烯乙酸酯的施密特型反应可以通过氮插入路径或酰基迁移路径进行重排,计算结果表明反应通过更具优势的酰基迁移路径实现施密特型重排从而得到2-吡啶酮化合物。第四章我们采用密度泛函理论对金催化炔烃、水和芳基重氮盐的炔烃三官能化反应的可能机理进行了探究。机理研究表明芳基重氮盐首先氧化Au(Ⅰ)物种形成芳基Au(Ⅲ)物种,作为π酸配体的Au(Ⅲ)物种可以活化炔烃进行分子内环化形成五元环氧鎓乙烯Au(Ⅲ)物种,五元环氧鎓乙烯基Au(Ⅲ)物种在碱性条件下被水解得到中性的2-羟基呋喃乙烯基Au(Ⅲ)物种,并对另一分子的芳基重氮盐亲核加成得到偶氮化合物,随后通过分子内开环以及Au(Ⅲ)的还原消除得到炔烃三官能团化产物。在该工作中芳基重氮盐既作为氧化剂又作为亲电试剂,为芳基重氮盐双功能作用提供了理论依据。第五章内容对α-芳基重氮酯和芳基重氮盐这两类重氮化合物的反应机理进行总结概括并对重氮化合物更多应用进行了展望。更多还原

【Abstract】 The synthesis and application of diazonium compounds have been studied since the end of the 19th century.Owing to their reactivity,aliphatic diazonium compounds and aryl diazonium salts are applied broadly in organic synthesis transformation.Aliphatic diazonium compounds have been widely used as precursors of metalcatalyzed carbene transfer reactions over the past years.With the continuous progress of visible light catalysis technology,visible light-promoted conversion of aliphatic diazonium compounds has received extensive attention due to its green and efficient characteristics.Unlike aliphatic diazo compounds,aryl diazonium salts can not only undergo a substitution reaction to remove the N2 group,but also can retain the N2 group to construct hydrazone,azo and polynitrogen-containing heterocyclic compounds that are difficult to be synthesized by other compounds.Although some progress has been made in experiment field,there are some mechanisms and the origin of chemoselectivity during the transformation of diazonium compounds which are not fully understood at this moment.In this thesis,density functional theory(DFT)is used to investigate the detailed mechanism of three transformation reactions involving aliphatic diazonium compounds and aryl diazonium salts.This thesis is mainly divided into five chapters:the first chapter provides a brief background to the background of the the basic knowledge of quantum chemistry,as well as the analytical methods used in the thesis and diazo compounds.From the second to fourth chapter,the photocatalytic multi-component coupling reaction of αaryldiazoesters,the gold-catalyzed Schmidt-type reaction of aryldiazonium salts and the gold-catalyzed trifunctionalization of aryldiazonium salts and alkynes were discussed,respectively.The following parts are the brief descriptions of the contents:In the second chapter,the mechanism and chemoselectivity of the visible lightcatalyzed multi-component coupling reaction of α-aryldiazoesters,amines,carbon dioxide and cyclic ethers are investigated by DFT.The mechanism obtained from DFT calculations reveals that the reaction starts from an electron-deficient carbene species,which could be provided from a diazoester under photocatalysis.The final products are?ependent on the stability of the oxonium intermediate,which is afforded by nucleophilic attack of the corresponding ether onto a carbene species.Energy decomposition analysis based on absolutely localized molecular orbitals shows that polarization and charge transfer is crucial for the stability of different oxonium ions,and this is related to the nucleophilicity of corresponding ethers.Therefore,the strong nucleophilic THF tends to obtain a four-component coupling product.In the third chapter,the mechanism and regioselectivity of the gold-catalyzed Schmidt-type reaction between 1,3-enyne acetate and aryldiazonium salts were investigated by DFT.Mechanistic studies show that the reaction firstly undergoes cationic Au(I)catalyzed Nazarov cyclization of 1,3-enyne acetates to generate cyclopentadienyl acetate.The 1,2-σ migration process determines the regioselectivity of this reaction.The Newman projections analysis show that the 1,2-σ migration of the secondary carbon would release strain and make it easier to obtain the desired cyclopentadienyl acetate intermediate.Two possible pathways for the Schmidt-type reaction of aryldiazonium salts with cyclopentadienyl acetate could happen:acyl transfer promoting rearrangement or nitrogen-insertive expansion.The calculation results show that the reaction through a more dominant acyl migration pathway to achieve the Schmidt-type rearrangement,thereby giving rise to the 2-pyridinone-based cyclic products.In the fourth chapter,the mechanism of the gold-catalyzed trifunctionalization of alkynes,water and aryldiazonium salts was investigated by DFT.Mechanistic studies indicate that aryldiazonium salts oxidize Au(Ⅰ)species to form Au(Ⅲ)species.Activated by the π-acetic Au(Ⅲ)cation,intramolecular cyclization of alkynes to form five-membered epoxy onium ethylene Au(Ⅲ)species.The five-membered epoxy onium vinyl Au(Ⅲ)species are hydrolyzed under alkaline conditions to obtain neutral 2-hydroxyfuran vinyl Au(Ⅲ)species.Subsequently,the azo compound is obtained by nucleophilic addition of another aryldiazonium salt.Finally,the trifunctional alkyne roduct is obtained by intramolecular ring-opening and reductive elimination of Au(Ⅲ).In this work,aryldiazonium salts act as both oxidants and electrophiles,the obtained insights provide a theoretical basis for the bifunctional action of aryldiazonium salts.The fifth chapter of this paper summarizes the reaction mechanism of two types of diazonium compounds and reveals more applications of diazonium compounds.更多还原