羧基导向C―H官能团化/脱羧偶联反应研究进展

以邻或对位取代苯甲酸为原料,通过羧基导向的芳香羧酸邻位碳氢键官能团化继而发生脱羧反应,在原羧基的邻位引入官能团,可以合成传统付-克反应难以合成的间位取代芳香化合物。在此类反应中,羧基充当无痕导向基的功能。本文综述了基于过渡金属催化羧基无痕导向的芳香羧酸脱羧偶联策略,形成新C―C、C―杂键的研究进展。     

基于“一石二鸟”策略的羧基无痕导向其邻位C—H键官能团化反应

C—H键作为有机化合物的基本单元,实现其直接的C—H键官能团化反应是简洁的合成方法.羧酸广泛存在于自然界,基于羧基的导向基团与离去基团双重角色所驱动的过渡金属催化羧酸邻位C—H键官能团化可控合成,不仅规避了C—H键活化过程中导向基团的额外引入与移除,也彰显了基于羧基“一石二鸟”策略的C—H键活化简洁性与脱羧绿色性.因此,基于“一石二鸟”策略的羧基无痕导向其邻位C—H键官能团化反应,能为可控定向合成提供新的策略和方法,在合成化学上具有显著意义.根据参与反应的偶联底物类型,分别介绍了基于“一石二鸟”策略的过渡金属催化羧酸邻位C—H键活化与含重键试剂、芳基化试剂及含杂原子试剂的反应,并对相关的一些反应机理进行了探讨.     

银催化的脱羧性偶联反应研究进展

过渡金属催化的脱羧性偶联反应已成为有机合成中一种非常重要的合成策略.结合本课题组的工作,探讨了银催化脱羧反应在Hunsdiecker型卤代反应、碳-碳键构筑、碳-杂键构筑、C—H键官能团化等方面的新应用,综述了近几年脂肪羧酸、α-酮酸和芳香羧酸的银催化脱羧性偶联反应领域的研究新进展.银催化剂可以在过硫酸盐或其他氧化剂协同作用的辅助下,引发自由基历程的选择性脱羧偶联,反应具有操作简单、无需隔绝水和空气、反应条件温和等特点,是一种可调控的自由基反应.     

脂肪族羧酸脱羧偶联反应研究进展

脱羧偶联反应是构建碳-碳键、碳-杂键以及活化碳-氢键的有效方法。该反应类型使用羧酸或羧酸盐作为底物,在催化剂的作用下可脱去二氧化碳并与其它化合物进行偶联反应。与传统的偶联反应相比,脱羧偶联反应具有对环境污染小、底物来源广等优点,因此该类型反应引起了研究者们的广泛关注。以芳香族羧酸进行的脱羧偶联反应已被报道,本文综述了近十年来各类催化体系下脂肪族羧酸进行脱羧偶联反应的研究进展。     

铜催化C—N,C—O偶联反应的研究进展

C—N,C—O键偶联是有机合成中的一类重要反应,铜催化的偶联反应是该类化学键形成中的主要手段之一,相比钯等过渡金属,金属铜具有低毒、廉价、反应条件温和等优点.按照所形成化合物的结构类型综述了铜催化C—N,C—O键偶联反应的最新研究进展.     

过渡金属催化羧基导向C—H官能团化研究进展

导向基团辅助的C—H活化是选择性活化分子中特定位置C—H键的重要措施,也是近年来有机化学研究的热点.羧酸作为一种高效导向基团具有价廉、低毒、容易修饰和作为无痕导向的优点而受到广大化学工作者的关注.按照羧基导向偶联方式的不同进行分类,综述了近年来过渡金属催化羧基导向C—H官能团化研究进展,并对代表性性反应机理做了简要说明.同时,对这一领域存在的问题和未来可能的发展方向进行了展望.     

C—S键构筑的研究进展

C—S键的构筑是有机合成的基础,对于天然产物、重要生物分子的合成和功能性材料的开发等具有重要作用,因此受到了广泛的关注.对近年来C—S键的构筑方面取得的进展进行了归纳,根据C—S键的成键方式不同,分别从C—H键活化、脱羧偶联反应、Ullmann反应这三个方面进行了总结,并从配体类型对Ullmann C—S成键展开论述.     

可见光催化脱羧偶联反应研究进展

可见光介入的偶联反应近年来得到了广泛的关注,已经发展成C—H活化、构建新型C—C、C—X键的重要方法之一.可见光催化体系的发展也为脱羧偶联反应提供了新的手段,许多关于可见光催化的脱羧反应研究见诸报端.对近年来可见光催化的脱羧反应进行了简要概述.     

过渡金属催化的硫酯的交叉偶联反应研究进展

硫酯在医药、农药、香精香料、材料等领域应用广泛,可从羧酸衍生得到,羧酸在自然界寻常可见、结构丰富.硫酯C(O)—S键能轻易和低价过渡金属发生氧化加成生成C(O)—M—S,该物种在不脱羰或脱羰情况下可以和亲核试剂反应构建碳碳键.近二十年来,人们广泛研究了过渡金属催化的硫酯的交叉偶联反应,这为从羧酸出发构筑C—C键提供了可供选择的有效方案.本综述按照过渡金属种类,依次对钯、镍、铜、铑等过渡金属催化的硫酯的交叉偶联反应进行了总结和讨论,综述了该类反应在天然产物、药物分子合成及其后期转化中的应用.同时关注了近些年报道的硫酯的不对称交叉偶联反应,以及硫酯的交叉偶联反应在串联反应和官能团转化方面的应用.     

芳基甲酰甲酸作为酰基化试剂应用的研究进展

近几年,芳基甲酰甲酸开始作为一种新的酰基化试剂应用于有机合成中。与其他酰基化试剂相比,其可以通过脱羧过程以亲核试剂的形式参与反应,具有反应活性高、反应条件温和的特点,大大拓展了酰基化反应的应用范围。本文综述了近几年芳基甲酰甲酸在偶联反应和碳氢键活化反应研究中的新应用和新进展。     

“水上”(“on water”)有机反应

"水上"有机反应的发展是水相绿色合成反应研究领域中的一个突破。体系的非均相性质是"水上"反应的基本特征。水不仅是重要的绿色反应介质,在大多数"水上"有机反应中都能观察到水对反应的速度和选择性有明显的提升作用。采用"水上"反应的条件,可以使反应的规模扩大,有利于产物的分离、纯化。本文以反应的类型分类综述了近年来有关"水上"有机反应研究的进展,以及在绿色有机合成中的应用。     

Photoredox-Catalyzed Decarboxylative Bromination,Chlorination and Thiocyanation Using Inorganic Salts

Decarboxylative halogenation reactions of alkyl carboxylic acids are highly valuable reactions for the synthesis of structurally diverse alkyl halides. However, many reported protocols rely on stoichiometric strong oxidants or highly electrophilic halogenating agents. Herein, we describe visible-light photoredox-catalyzed decarboxylative halogenation reactions of N-hydroxyphthalimide-activated carboxylic acids that avoid stoichiometric oxidants and use inexpensive inorganic halide salts as the halogenating agents. Bromination with lithium bromide proceeds under simple, transition-metal-free conditions using an organic photoredox catalyst and no other additives, whereas dual photoredox-copper catalysis is required for chlorination with lithium chloride. The mild conditions display excellent functional-group tolerance, which is demonstrated through the transformation of a diverse range of structurally complex carboxylic acid containing natural products into the corresponding alkyl bromides and chlorides. In addition, we show the generality of the dual photoredox-copper-catalyzed decarboxylative functionalization with inorganic salts by extension to thiocyanation with potassium thiocyanide, which was applied to the synthesis of complex alkyl thiocyanates.     

超临界二氧化碳介质中的有机反应

本文主要介绍了近5年来超临界二氧化碳中有机反应研究的最新进展,包括加氢反应、氧化反应、羰基化反应、碳碳键形成反应、酯化反应和酶催化反应的研究现状;同时,还介绍了超临界二氧化碳作为反应底物用于合成碳酸酯和氨基甲酸酯的研究进展;并对未来的发展进行了展望。     

Decarboxylative coupling reactions: a modern strategy for C-C-bond formation

This critical review examines transition metal-catalyzed decarboxylative couplings that have emerged within recent years as a powerful strategy to form carbon-carbon or carbon-heteroatom bonds starting from carboxylic acids. In these reactions, C-C bonds to carboxylate groups are cleaved, and in their place, new carbon-carbon bonds are formed. Decarboxylative cross-couplings constitute advantageous alternatives to traditional cross-coupling or addition reactions involving preformed organometallic reagents. Decarboxylative reaction variants are also known for Heck reactions, direct arylation processes, and carbon-heteroatom bond forming reactions.     

CO_2/H_2O混合绿色介质中的有机催化反应

绿色化学是化学发展的必然趋势。有效利用绿色溶剂是绿色化学的重要内容。CO2和H2O混合体系是具有很多特点的绿色反应介质,可以用于不同化学反应,特别是弱酸催化的反应,从而替代传统的有机酸和无机酸。本文讨论了CO2/H2O体系的酸性随温度和压力的变化,综述了在CO2/H2O混合绿色介质中有机化学反应研究进展,这些反应包括脱水反应、烷基化反应、香茅醛环化反应、重氮化反应、多元醇转化成环醚的反应、溴氧化反应、芳硝基化合物选择性还原、多糖水解反应、生物质转化反应、环氧丙烷水解反应、脱羧反应、醇氧化反应、对映选择氧化反应以及酮不对称还原;最后对CO2/H2O体系在化学反应中应用的发展趋势进行了探讨。     

无溶剂条件下的不对称催化反应

本文综述了近年来在无溶剂条件下进行的一些不对称催化反应的进展,着重介绍了无溶剂条件下的不对称Aldol反应、环氧化合物不对称开环反应、外消旋环氧化合物的拆分、不对称Diels-Alder反应、金属有机试剂对醛酮的不对称加成反应、不对称氢化反应、不对称氢甲酰化反应、不对称烯烃复分解反应、不对称Michael加成反应、不对称氧化反应、不对称Friedel-Crafts反应等,同时展望了无溶剂不对称催化反应的研究前景。     

Electrophotocatalytic Decarboxylative C−H Functionalization of Heteroarenes

Decarboxylative C?H functionalization reactions are highly attractive methods for forging carbon–carbon bonds considering their inherent step‐ and atom‐economical features and the pervasiveness of carboxylic acids and C?H bonds. An ideal approach to achieve these dehydrogenative transformations is through hydrogen evolution without using any chemical oxidants. However, effective couplings by decarboxylative carbon–carbon bond formation with proton reduction remain an unsolved challenge. Herein, we report an electrophotocatalytic approach that merges organic electrochemistry with photocatalysis to achieve the efficient direct decarboxylative C?H alkylation and carbamoylation of heteroaromatic compounds through hydrogen evolution. This electrophotocatalytic method, which combines the high efficiency and selectivity of photocatalysis in promoting decarboxylation with the superiority of electrochemistry in effecting proton reduction, enables the efficient coupling of a wide range of heteroaromatic bases with a variety of carboxylic acids and oxamic acids. Advantageously, this method is scalable to decagram amounts, and applicable to the late‐stage functionalization of drug molecules.     

Electrophotocatalytic Decarboxylative C−H Functionalization of Heteroarenes

Decarboxylative C−H functionalization reactions are highly attractive methods for forging carbon–carbon bonds considering their inherent step- and atom-economical features and the pervasiveness of carboxylic acids and C−H bonds. An ideal approach to achieve these dehydrogenative transformations is through hydrogen evolution without using any chemical oxidants. However, effective couplings by decarboxylative carbon–carbon bond formation with proton reduction remain an unsolved challenge. Herein, we report an electrophotocatalytic approach that merges organic electrochemistry with photocatalysis to achieve the efficient direct decarboxylative C−H alkylation and carbamoylation of heteroaromatic compounds through hydrogen evolution. This electrophotocatalytic method, which combines the high efficiency and selectivity of photocatalysis in promoting decarboxylation with the superiority of electrochemistry in effecting proton reduction, enables the efficient coupling of a wide range of heteroaromatic bases with a variety of carboxylic acids and oxamic acids. Advantageously, this method is scalable to decagram amounts, and applicable to the late-stage functionalization of drug molecules.     

离子液体中的不对称催化反应

对价格昂贵的手性催化剂进行回收和重复利用是目前不对称催化领域面临的难题之一,受到学术界和工业界的共同关注。化学家们已经尝试了许多方法,其中使用离子液体来替代常规有机溶剂使催化剂得到分离和重新使用已经引起他们极大的兴趣。本文综述了近年来在离子液体中进行不对称催化反应的研究进展,对离子液体中过渡金属和有机小分子催化的各种反应进行重点介绍,强调了离子液体不但在催化剂回收方面有独特优势,而且在许多反应中能够提高催化效率。     

Silver-catalyzed decarboxylative chlorination of aliphatic carboxylic acids

Decarboxylative halogenation of carboxylic acids, the Hunsdiecker reaction, is one of the fundamental functional group transformations in organic chemistry. As the initial method requires the preparations of strictly anhydrous silver carboxylates, several modifications have been developed to simplify the procedures. However, these methods suffer from the use of highly toxic reagents, harsh reaction conditions, or limited scope of application. In addition, none is catalytic for aliphatic carboxylic acids. In this Article, we report the first catalytic Hunsdiecker reaction of aliphatic carboxylic acids. Thus, with the catalysis of Ag(Phen)(2)OTf, the reactions of carboxylic acids with t-butyl hypochlorite afforded the corresponding chlorodecarboxylation products in high yields under mild conditions. This method is not only efficient and general, but also chemoselective. Moreover, it exhibits remarkable functional group compatibility, making it of more practical value in organic synthesis. The mechanism of single electron transfer followed by chlorine atom transfer is proposed for the catalytic chlorodecarboxylation.