Tetrahedron Letters最新文献

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Functionalization of Lewis base (LB) in LB–BR3 adducts LB - br3加合物中路易斯碱（LB）的功能化

IF 1.5 4区化学 Q3 CHEMISTRY, ORGANIC

Tetrahedron Letters

Pub Date : 2024-11-26 DOI: 10.1016/j.tetlet.2024.155372

Pan Xu , Xuenian Chen , Zhenxing Liu

Whenever a Lewis base borane is formed, the Lewis base will affect the properties of borane. The opposite is similarly true, that borane will affect the properties of Lewis base. The current development of Lewis base borane adducts mainly focuses on the borane part. Less chemistry is known about the Lewis base part. Herein, we selected examples to highlight the functionalization of the Lewis base of LB–BR₃ adducts. Parts I and II focus on showing how boranes promote coupling, substitution, and reduction reactions of amine and phosphine in the corresponding borane adducts, as well as borane’s control of the regioselectivity and stereoselectivity of amine-boron and phosphine-borane analogs. Part III focuses on the effect of boranes on the chemistry of Lewis bases containing carbon, oxygen, and sulfur.

当硼烷形成路易斯碱时，路易斯碱会影响硼烷的性质。反之亦然，硼会影响路易斯碱的性质。目前路易斯碱硼烷加合物的研究主要集中在硼烷部分。人们对路易斯碱的化学反应知之甚少。在此，我们选择了一些例子来强调LB-BR3加合物的路易斯碱的功能化。第一部分和第二部分重点展示了硼烷如何促进相应硼烷加合物中胺和膦的偶联、取代和还原反应，以及硼烷对胺-硼和膦-硼烷类似物的区域选择性和立体选择性的控制。第三部分着重于硼烷对含有碳、氧和硫的路易斯碱的化学作用。

引用次数: 0

Synthesis of 1,4-benzodioxepinones via electrochemical oxyselenenylation of 2-O-tethered alkenyl benzoic acid and diselenides 2- o系链烯基苯甲酸和二硒烯酸的电化学氧硒化合成1,4-苯并二苯二酮类化合物

IF 1.5 4区化学 Q3 CHEMISTRY, ORGANIC

Tetrahedron Letters

Pub Date : 2024-11-24 DOI: 10.1016/j.tetlet.2024.155389

Junsheng Hou , Bingxin You , Ruiqi Lv , Xinxin Zhang , Hao Zhang , Qiang Liu

An efficient methodology for the synthesis of seven-membered benzodioxepinones has been developed via electrochemical oxyselenenylation of 2-O-tethered alkenyl benzoic acid and diselenides under an external oxidant-free condition at room temperature. The experimental evidence supports this transformation through a radical mechanism.

建立了一种在室温条件下，以2- o系链烯基苯甲酸和二苯二烯为原料，在无氧化剂的条件下，电化学氧化硒化合成七元苯并二苯二酮的有效方法。实验证据支持这种转变是通过一种自由基机制实现的。

引用次数: 0

Convenient synthesis of O-alkylated/N-acylated polyhydroxyazepane based compounds for modulating MD-2-TLR4 complex formation 方便合成 O-烷基化/N-酰基化多羟基氮杂环庚烷基化合物，用于调节 MD-2-TLR4 复合物的形成

IF 1.5 4区化学 Q3 CHEMISTRY, ORGANIC

Tetrahedron Letters

Pub Date : 2024-11-23 DOI: 10.1016/j.tetlet.2024.155388

Sumit , Sudipta Nandi , Indrapal Singh Aidhen

Toll-like receptor 4 (TLR4) is a critical component of the innate immune system, recognizing lipopolysaccharide (LPS) from Gram-negative bacteria and triggering immune responses. The activation of TLR4 involves several key steps, including interactions with LPS-binding protein (LBP), CD14, and myeloid differentiation protein 2 (MD-2), culminating in the formation of the (LPS.MD-2 TLR4)₂ complex. Structural insights show that LPS acyl chains insert into the hydrophobic pocket of MD-2, driving TLR4 activation. Inspired by this understanding, numerous natural and synthetic compounds have been developed to inhibit TLR4 by targeting the MD-2/TLR4 complex. Eritoran 1, is one such illustration. The conformational flexibility of azepane architecture inspired us to visualize O-alkylated/N-acylated polyhydroxyazepane-based compounds toward this objective. The docking studies and molecular simulation studies supported the rationale. Synthesis of O-alkylated/N-acylated polyhydroxyazepane-based compounds 2-4 (a-h) through a key building block is described herein.

Toll 样受体 4（TLR4）是先天性免疫系统的重要组成部分，它能识别革兰氏阴性细菌的脂多糖（LPS）并触发免疫反应。TLR4 的激活涉及几个关键步骤，包括与 LPS 结合蛋白（LBP）、CD14 和髓样体分化蛋白 2（MD-2）相互作用，最终形成（LPS.MD-2 TLR4）2 复合物。结构研究表明，LPS酰基链插入了MD-2的疏水口袋，从而推动了TLR4的激活。受这一认识的启发，人们开发了许多天然和合成化合物，通过靶向 MD-2/TLR4 复合物来抑制 TLR4。厄里托兰 1 就是这样一个例子。氮杂环庚烷结构的构象灵活性启发我们朝着这一目标研究 O-烷基化/N-酰基化的多羟基氮杂环庚烷化合物。对接研究和分子模拟研究支持了这一观点。本文介绍了通过关键结构单元合成 O-烷基化/N-酰基化多羟基氮杂环庚烷基化合物 2-4（a-h）的过程。

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引用次数: 0

A practical synthesis of Cbz protected (1R,2R) and (1S,2S) 2-hydroxy-cyclobutylamines Cbz保护的（1R,2R）和（1S,2S） 2-羟基环丁胺的实际合成

IF 1.5 4区化学 Q3 CHEMISTRY, ORGANIC

Tetrahedron Letters

Pub Date : 2024-11-23 DOI: 10.1016/j.tetlet.2024.155391

Can Jin, Yilin Wang, Xiangsheng Xu, Xiaoqing Li

(1R,2R) and (1S,2S) 2-hydroxy-cyclobutylamines are important substructures in a range of bio-active molecules and pharmaceutical candidates. In view of the potential safety issues and the low reaction efficiency associated with the earlier published synthetic process, which relies on Curtius rearrangement for the synthesis of 2-amino-cyclobutanone intermediate, a more practical and efficient process to prepare (1R,2R) and (1S,2S) 2-hydroxy-cyclobutylamines using readily available N-Cbz-2-amino-cyclobutanone was developed. Cbz protected (1R,2R) 2-hydroxy-cyclobutylamine could be synthesized in 14 % yield over 5 steps.

（1R,2R）和（1S,2S） 2-羟基环丁胺是一系列生物活性分子和候选药物的重要亚结构。鉴于先前发表的依赖Curtius重排法合成2-氨基环丁酮中间体的合成工艺存在安全隐患和反应效率低的问题，本研究开发了一种更实用、更高效的利用n - cbz -2-氨基环丁酮制备（1R,2R）和（1S,2S） 2-羟基环丁胺的工艺。Cbz保护的（1R,2R） 2-羟基环丁胺在5步内以14%的收率合成。

引用次数: 0

Efficient synthesis of highly substituted benzoselenazole derivatives through the one-pot, multi-step Ullmann coupling reaction 一锅多步乌尔曼偶联反应高效合成高取代苯并硒唑衍生物

IF 1.5 4区化学 Q3 CHEMISTRY, ORGANIC

Tetrahedron Letters

Pub Date : 2024-11-23 DOI: 10.1016/j.tetlet.2024.155387

Manijeh Nematpour

In this research, the simple and efficient method for the synthesis of highly substituted benzoselenazole derivatives using the one-pot, multi-step Ullman coupling reaction of acyl isoselenocyanate-nitro compounds adducts and dihalobenzene in the vicinity of K₂CO₃ as a base, copper iodide, at room temperature, and in MeCN solvent has been done successfully. The use of simple and available raw materials, mild copper catalytic reaction conditions, easy purification with the help of solvent, and finally the synthesis of 16 new compounds from the benzoselenazoles family are notable features of this protocol.

在本研究中，以K2CO3附近的二卤苯为碱，以碘化铜为基料，在室温下，在MeCN溶剂中，采用一锅多步Ullman偶联反应，成功地合成了高取代苯并硒酸盐-硝基化合物的酰基异硒氰酸酯-硝基化合物加合物和二卤苯。采用简单易得的原料，温和的铜催化反应条件，容易借助溶剂提纯，最终合成了16个苯并硒化唑类化合物，是本方案的显著特点。

引用次数: 0

Biomimetic oxidation of tetracycline and derivatives at C11a 四环素及其 C11a 衍生物的生物模拟氧化作用

IF 1.5 4区化学 Q3 CHEMISTRY, ORGANIC

Tetrahedron Letters

Pub Date : 2024-11-22 DOI: 10.1016/j.tetlet.2024.155366

He Wu, Yong Wang, Guangguang Yang, Karuppu Selvaraj, Gang Chen

Tetracycline destructases (TDases), a type of TC-inactivating enzymes, inactivate all known TC antibiotics by C11a oxidation, which is considered as a clinical threat. To provide more information on this enzymatic inactivation and oxygenated TCs, we report here a chemical oxidation of Tetracycline and its derivatives at the C11a position using m-CPBA with additives via biomimetic pathways. The structures of the oxygen-containing TCs (2h, 2i) were confirmed by X-ray analysis, and further transformations were performed with oxygen-containing TCs (2e, 2i).

四环素破坏酶（TDases）是四环素类抗生素失活酶的一种，它通过 C11a 氧化作用使所有已知的四环素类抗生素失活，这被认为是一种临床威胁。为了提供更多有关这种酶失活和含氧三环素的信息，我们在此报告利用 m-CPBA 和添加剂通过仿生途径对四环素及其衍生物的 C11a 位进行化学氧化。含氧三氯乙酸的结构（2h、2i）已通过 X 射线分析得到证实，含氧三氯乙酸的进一步转化（2e、2i）也已完成。

引用次数: 0

Synthesis of 2,4,5-vinylic-trisubstituted oxazoles via a Palladium-catalyzed cascade coupling reaction 通过钯催化级联偶联反应合成 2,4,5-乙烯基三取代噁唑

IF 1.5 4区化学 Q3 CHEMISTRY, ORGANIC

Tetrahedron Letters

Pub Date : 2024-11-21 DOI: 10.1016/j.tetlet.2024.155373

Jun Ma , Huali Wang , Qingyu Meng , Haoyue Wang , Fangyi Li , Zheng Li

A novel one-step synthesis of valuable 2,4,5-vinylic-trisubstituted oxazoles is described. This reaction, utilizing readily available β,β-dibrominated secondary enamides and terminal alkenes as starting materials, occurs via a ligand-free Palladium-catalyzed cascade intramolecular CO coupling/intermolecular Heck reaction.

本文介绍了一步合成有价值的 2,4,5-乙烯基三取代噁唑的新方法。该反应以现成的 β,β-二溴化仲烯酰胺和末端烯为起始原料，通过无配体钯催化的级联分子内 CO 偶联/分子间 Heck 反应进行。

引用次数: 0

The first enantioselective total synthesis of the eremophilane-type sesquiterpenoid (−)-peniroqueforin C 首次对映选择性全合成乙内酰脲类倍半萜化合物 (-)-peniroqueforin C

IF 1.5 4区化学 Q3 CHEMISTRY, ORGANIC

Tetrahedron Letters

Pub Date : 2024-11-20 DOI: 10.1016/j.tetlet.2024.155386

Sudhir R. Ingale , Ramavath Vinodkumar , Ravindar Kontham

Herein, we report the first stereoselective total synthesis of the eremophilane-type sesquiterpenoid (−)-peniroqueforin C using a chiral-pool strategy. This synthetic route features the use of readily available (S)-(+)-carvone as a chiral building block, Robinson annulation to construct the decalin system, substrate-controlled stereoselective methylation, single-step annulative construction of a tricyclic γ-ylidene-butenolide with concomitant alkene transposition, and direct lactone-to-lactam conversion as key transformations.

在此，我们报告了利用手性池策略首次立体选择性地全合成了埃利莫非兰类倍半萜化合物 (-)-peniroqueforin C。这条合成路线的特点是：使用现成的(S)-(+)-香芹酮作为手性构筑基块，通过罗宾逊环化反应构建癸醛苷体系，进行底物控制的立体选择性甲基化，单步环化构建三环γ-亚基丁烯内酯并同时进行烯烃转位，以及作为关键转化过程的内酯-内酰胺直接转化。

引用次数: 0

Palladium-catalyzed cycloisomerization of thiocarbamates with consecutive formation of quaternary carbon and sulfide 钯催化硫代氨基甲酸酯的环异构化，并连续形成季碳和硫化物

IF 1.5 4区化学 Q3 CHEMISTRY, ORGANIC

Tetrahedron Letters

Pub Date : 2024-11-19 DOI: 10.1016/j.tetlet.2024.155384

Hyu Kumazawa, Masahisa Nakada

The Pd-catalyzed cycloisomerization of thiocarbamates with consecutive formation of a quaternary carbon and a sulfide is described. This Pd-catalyzed cascade reaction occurred with both alkylthiocarbamates and arylthiocarbamates, and arylthiocarbamates reacted faster than alkylthiocarbamates. The Pd-catalyzed cycloisomerization can be applied to phenylene- and alkylene-tethered substrates, and thiocarbamate was found to be less reactive than carbamimidothioate. The Pd-catalyzed cycloisomerization can be used to form bridged rings and is expected to be useful for ring construction of nitrogen-containing polycyclic natural products.

本研究描述了 Pd 催化的硫代氨基甲酸酯环异构化反应，该反应会连续生成一个季碳和一个硫化物。烷基硫代氨基甲酸酯和芳基硫代氨基甲酸酯都发生了这种 Pd 催化级联反应，而芳基硫代氨基甲酸酯的反应速度快于烷基硫代氨基甲酸酯。Pd 催化的环异构化反应可用于苯系和烯系底物，而且发现硫代氨基甲酸酯的反应性比硫代氨基甲酰亚胺低。Pd 催化的环异构化反应可用于形成桥环，并有望用于含氮多环天然产物的环构建。

引用次数: 0

Enantioselective gold/enzyme dual catalysis 对映选择性金/酶双催化

IF 1.5 4区化学 Q3 CHEMISTRY, ORGANIC

Tetrahedron Letters

Pub Date : 2024-11-19 DOI: 10.1016/j.tetlet.2024.155382

Amit Patwa, Chayanika Pegu, Bidisha Paroi, Nitin T. Patil

Over the decades, enantioselective metal/enzyme dual catalysis has emerged as a dynamic area of research in asymmetric synthesis. By leveraging the unique reactivities of metal/enzyme dual catalysis, numerous transformations have been developed, primarily relying on metals such as Pd, Ru, Ir, Fe and Au. Among all transition metals, gold stands out as the catalyst of choice due to its soft π-acidic nature. The π-activation reactivities of gold catalysts have been strategically integrated with enzyme catalysis, thereby leading to highly enantioselective transformations that are unattainable via a single catalyst alone. This review endeavors to provide an overview of the advancements in enantioselective gold/enzyme dual catalysis.

几十年来，对映选择性金属/酶双重催化已成为不对称合成领域中一个充满活力的研究领域。利用金属/酶双催化的独特反应活性，人们开发出了许多转化方法，主要依赖于 Pd、Ru、Ir、Fe 和 Au 等金属。在所有过渡金属中，金因其软π酸性而成为首选催化剂。金催化剂的π-活化反应性已与酶催化进行了战略整合，从而实现了单个催化剂无法实现的高对映选择性转化。本综述旨在概述对映选择性金/酶双重催化方面的进展。

引用次数: 0

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