Pub Date : 2025-12-12DOI: 10.1016/j.tet.2025.135091
Xi Xiang , Minghui Xie , Hongran Chen , Zixin Deng , Gen Li , Xiaohui Yan , Min Xu , Anwei Hou
Bacterial terpene synthases (TPSs) represent a valuable source of enzymatic diversity for the discovery of novel terpenoid structures. Here, we report the functional characterization of two diterpene synthases, GTC2 and E2E2, from Chitinophaga species. Heterologous expression and biochemical assays demonstrated that both enzymes can utilize farnesyl diphosphate (FPP) and geranylgeranyl diphosphate (GGPP) to produce distinct terpene profiles. Six diterpenes (5–10) were isolated, including two new compounds (8 and 9), for which their structures and relative configurations were elucidated and plausible formation mechanisms were proposed. Structural modeling, molecular docking, and mutagenesis revealed that residue Y293 plays a key role in determining the product specificity of E2E2. Y293 N substitution significantly altered the product profile, affording three known diterpenes (11–13), one of which (11) was confirmed by X-ray crystallography. This study expands the known diterpene diversity of Chitinophaga and provides insights into the structure–function relationship of bacterial diterpene synthases.
{"title":"Characterization of two diterpene synthases from Chitinophaga species","authors":"Xi Xiang , Minghui Xie , Hongran Chen , Zixin Deng , Gen Li , Xiaohui Yan , Min Xu , Anwei Hou","doi":"10.1016/j.tet.2025.135091","DOIUrl":"10.1016/j.tet.2025.135091","url":null,"abstract":"<div><div>Bacterial terpene synthases (TPSs) represent a valuable source of enzymatic diversity for the discovery of novel terpenoid structures. Here, we report the functional characterization of two diterpene synthases, GTC2 and E2E2, from <em>Chitinophaga</em> species. Heterologous expression and biochemical assays demonstrated that both enzymes can utilize farnesyl diphosphate (FPP) and geranylgeranyl diphosphate (GGPP) to produce distinct terpene profiles. Six diterpenes (<strong>5</strong>–<strong>10</strong>) were isolated, including two new compounds (<strong>8</strong> and <strong>9</strong>), for which their structures and relative configurations were elucidated and plausible formation mechanisms were proposed. Structural modeling, molecular docking, and mutagenesis revealed that residue Y293 plays a key role in determining the product specificity of E2E2. Y293 N substitution significantly altered the product profile, affording three known diterpenes (<strong>11</strong>–<strong>13</strong>), one of which (<strong>11</strong>) was confirmed by X-ray crystallography. This study expands the known diterpene diversity of <em>Chitinophaga</em> and provides insights into the structure–function relationship of bacterial diterpene synthases.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"191 ","pages":"Article 135091"},"PeriodicalIF":2.2,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145786969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.tet.2025.135096
Huabin Wang , Qiaoli Li , Feiyang Long , Tiantian Zhou , Zeyu Zhang , Songlin Zhang , Zhen Yao , Ying Zhou , Qiang Huang
An efficient and eco-friendly protocol to synthesize C2-phosphorylated 2,3-dihydrochromones was developed via Brønsted acid-promoted selective addition of chromones with H-phosphine oxides. The reaction exhibits a broad substrate scope, shows good compatibility with various functional groups, affords high yields and is amenable to gram - scale synthesis. This strategy, mediated by Brønsted acid, proceeded smoothly under mild and simple conditions without any metal catalyst or oxidant, providing an alternative approach to access C2-phosphorylated 2,3-dihydrochromones.
{"title":"Brønsted acid-promoted selective addition of chromones with H-phosphine oxides for synthesis of C2-Phosphorylated 2,3-2H-chromones","authors":"Huabin Wang , Qiaoli Li , Feiyang Long , Tiantian Zhou , Zeyu Zhang , Songlin Zhang , Zhen Yao , Ying Zhou , Qiang Huang","doi":"10.1016/j.tet.2025.135096","DOIUrl":"10.1016/j.tet.2025.135096","url":null,"abstract":"<div><div>An efficient and eco-friendly protocol to synthesize C2-phosphorylated 2,3-dihydrochromones was developed via Brønsted acid-promoted selective addition of chromones with H-phosphine oxides. The reaction exhibits a broad substrate scope, shows good compatibility with various functional groups, affords high yields and is amenable to gram - scale synthesis. This strategy, mediated by Brønsted acid, proceeded smoothly under mild and simple conditions without any metal catalyst or oxidant, providing an alternative approach to access C2-phosphorylated 2,3-dihydrochromones.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"191 ","pages":"Article 135096"},"PeriodicalIF":2.2,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145786968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.tet.2025.135088
Xiaoyu Liao , Zhiyun Zhao , Jiyi Lv , Xiling Deng , Xinrun Zhao , Yangzi Chen , Wei Zhang , Pinghua Sun , Xinhui Pan
An efficient copper(Ⅰ) bromide catalyzed 1,3-dipolar cycloaddition reaction of different α-nitroketones with dipolarophiles has been investigated. These reactions afford the corresponding 3-benzoylisoxazolines in moderate to high yields (up to 99.9 %) under mild conditions. This method provides an economical and simple route to construction of isoxazole or isoxazoline ring.
{"title":"Synthesis of 3-benzoylisoxazolines by copper(Ⅰ) bromide-catalyzed 1,3-dipolar cycloaddition of nitroketones with dipolarophiles","authors":"Xiaoyu Liao , Zhiyun Zhao , Jiyi Lv , Xiling Deng , Xinrun Zhao , Yangzi Chen , Wei Zhang , Pinghua Sun , Xinhui Pan","doi":"10.1016/j.tet.2025.135088","DOIUrl":"10.1016/j.tet.2025.135088","url":null,"abstract":"<div><div>An efficient copper(Ⅰ) bromide catalyzed 1,3-dipolar cycloaddition reaction of different α-nitroketones with dipolarophiles has been investigated. These reactions afford the corresponding 3-benzoylisoxazolines in moderate to high yields (up to 99.9 %) under mild conditions. This method provides an economical and simple route to construction of isoxazole or isoxazoline ring.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"192 ","pages":"Article 135088"},"PeriodicalIF":2.2,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145838303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.tet.2025.135092
Veronica B. Hubble , Camila A. Suarez , Primali V. Navaratne , Isabel M. de la Torre Roehl , Alfred N. Fonteh , Michael G. Harrington , Michael D. Bartberger , Scott C. Virgil , Brian M. Stoltz
We report the syntheses of seven novel bufalin derivatives and four digitoxigenin derivatives, inspired by the high affinity of bufalin and digitoxigenin to a ubiquitous enzyme called the Na+, K+–ATPase and their biological potential as brain Na+, K+–ATPase modulators. We sought to design and synthesize derivatives that more closely obey CNS-penetrant guidelines set forth by the medicinal chemistry community compared to their natural product class counterparts, by reducing the number of hydrogen bond donors or acceptors and increasing lipophilicity. In addition, we highlight the necessity of a C14 bulky protecting group in the steroid core to set a desired C17-β stereocenter for the synthesis of C17-β-pyridines or pyridones.
{"title":"Synthesis of bufalin and digitoxigenin derivatives","authors":"Veronica B. Hubble , Camila A. Suarez , Primali V. Navaratne , Isabel M. de la Torre Roehl , Alfred N. Fonteh , Michael G. Harrington , Michael D. Bartberger , Scott C. Virgil , Brian M. Stoltz","doi":"10.1016/j.tet.2025.135092","DOIUrl":"10.1016/j.tet.2025.135092","url":null,"abstract":"<div><div>We report the syntheses of seven novel bufalin derivatives and four digitoxigenin derivatives, inspired by the high affinity of bufalin and digitoxigenin to a ubiquitous enzyme called the Na<sup>+</sup>, K<sup>+</sup>–ATPase and their biological potential as brain Na<sup>+</sup>, K<sup>+</sup>–ATPase modulators. We sought to design and synthesize derivatives that more closely obey CNS-penetrant guidelines set forth by the medicinal chemistry community compared to their natural product class counterparts, by reducing the number of hydrogen bond donors or acceptors and increasing lipophilicity. In addition, we highlight the necessity of a C14 bulky protecting group in the steroid core to set a desired C17-β stereocenter for the synthesis of C17-β-pyridines or pyridones.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"193 ","pages":"Article 135092"},"PeriodicalIF":2.2,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145974198","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-11DOI: 10.1016/j.tet.2025.135090
Divyani P. Patel, Vishwa K. Patel, Satish Kumar Singh
Vinyl sulfones are valued for their unique chemical properties and bioactivity, but creating a wide range of different analogs remains a challenge. To address this limitation, we have developed a novel and eco-friendly method for the synthesis of (E)-vinyl sulfones via visible light-mediated deborative sulfonylation of alkenyl boronic acids with sulfonyl hydrazides. Our straightforward and metal-free sulfonylation utilises eco-friendly visible light irradiation, and rose bengal organic dye, while a water-ethanol mixture serves as a green solvent, removing the necessity for external oxidants. The reaction delivers (E)-vinyl sulfones in good to excellent yields within a short reaction time and exhibits broad substrate scope with excellent functional group tolerance, including electron-rich, electron-poor, as well as aliphatic, heteroaryl, and sterically hindered substituent derivatives. Mechanistic investigations support a photoredox single-electron transfer (SET) pathway involving sulfonyl radicals. This mild and environmentally friendly protocol provides a valuable approach for the synthesis of bioactive (E)-vinyl sulfones, which are key structural motifs in pharmaceuticals, agrochemicals, and material science.
{"title":"Photocatalytic deborative sulfonylation of alkenyl boronic acids with sulfonyl hydrazides under green environmental conditions","authors":"Divyani P. Patel, Vishwa K. Patel, Satish Kumar Singh","doi":"10.1016/j.tet.2025.135090","DOIUrl":"10.1016/j.tet.2025.135090","url":null,"abstract":"<div><div>Vinyl sulfones are valued for their unique chemical properties and bioactivity, but creating a wide range of different analogs remains a challenge. To address this limitation, we have developed a novel and eco-friendly method for the synthesis of (<em>E</em>)-vinyl sulfones <em>via</em> visible light-mediated deborative sulfonylation of alkenyl boronic acids with sulfonyl hydrazides. Our straightforward and metal-free sulfonylation utilises eco-friendly visible light irradiation, and rose bengal organic dye, while a water-ethanol mixture serves as a green solvent, removing the necessity for external oxidants. The reaction delivers (<em>E</em>)-vinyl sulfones in good to excellent yields within a short reaction time and exhibits broad substrate scope with excellent functional group tolerance, including electron-rich, electron-poor, as well as aliphatic, heteroaryl, and sterically hindered substituent derivatives. Mechanistic investigations support a photoredox single-electron transfer (SET) pathway involving sulfonyl radicals. This mild and environmentally friendly protocol provides a valuable approach for the synthesis of bioactive (<em>E</em>)-vinyl sulfones, which are key structural motifs in pharmaceuticals, agrochemicals, and material science.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"191 ","pages":"Article 135090"},"PeriodicalIF":2.2,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145786973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-08DOI: 10.1016/j.tet.2025.135089
Rajaghatta N. Suresh , Toreshettahally R. Swaroop , Kanchugarakoppal S. Rangappa
Copper-catalyzed/mediated synthesis of heterocycles plays a crucial role in the field of medicinal chemistry as well as synthetic organic chemistry. Notably, copper salts facilitate the C-S bond formation during the synthesis of heterocycles. On the other hand, they also serve as oxidizing agents, metal catalysts and Lewis acids. This review summarizes an updated collection of copper-catalyzed/mediated synthesis of thiophenes and benzothiophenes. Furthermore, optimal reaction conditions, reaction's scope/generality, pros and/or cons, discussion of control experiments and plausible mechanisms of the reactions are presented. In addition, this review article collects important strategies of copper-catalyzed/mediated synthesis of thiophenes and benzothiophenes reported from 2010 to 2024, which is advantageous for many chemists interested in transition metal-catalyzed reactions.
{"title":"Copper-catalyzed/mediated synthesis of thiophenes and benzothiophenes: an updated review","authors":"Rajaghatta N. Suresh , Toreshettahally R. Swaroop , Kanchugarakoppal S. Rangappa","doi":"10.1016/j.tet.2025.135089","DOIUrl":"10.1016/j.tet.2025.135089","url":null,"abstract":"<div><div>Copper-catalyzed/mediated synthesis of heterocycles plays a crucial role in the field of medicinal chemistry as well as synthetic organic chemistry. Notably, copper salts facilitate the C-S bond formation during the synthesis of heterocycles. On the other hand, they also serve as oxidizing agents, metal catalysts and Lewis acids. This review summarizes an updated collection of copper-catalyzed/mediated synthesis of thiophenes and benzothiophenes. Furthermore, optimal reaction conditions, reaction's scope/generality, pros and/or cons, discussion of control experiments and plausible mechanisms of the reactions are presented. In addition, this review article collects important strategies of copper-catalyzed/mediated synthesis of thiophenes and benzothiophenes reported from 2010 to 2024, which is advantageous for many chemists interested in transition metal-catalyzed reactions.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"191 ","pages":"Article 135089"},"PeriodicalIF":2.2,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-02DOI: 10.1016/j.tet.2025.135067
Qing Shen , Shuangqiao Li , Xianglin Zhong , Yang-Bao Miao , Jiahong Li
This study developed a novel photocatalyst-free, visible-light-driven strategy for the synthesis of diaryl ethers. Utilizing 455 nm blue light to excite nitroarenes and enhance their electrophilicity, the method efficiently constructs C–O bonds via an SNAr reaction between nitroarenes and phenolic compounds under mild alkaline conditions. This approach eliminates the need for transition metals, operates at room temperature under mild conditions, exhibits broad substrate scope, and offers simple operation, thereby providing a green and efficient new pathway for diaryl ether synthesis.
{"title":"Visible-light-promoted synthesis of diaryl ethers from nitroarenes and phenols","authors":"Qing Shen , Shuangqiao Li , Xianglin Zhong , Yang-Bao Miao , Jiahong Li","doi":"10.1016/j.tet.2025.135067","DOIUrl":"10.1016/j.tet.2025.135067","url":null,"abstract":"<div><div>This study developed a novel photocatalyst-free, visible-light-driven strategy for the synthesis of diaryl ethers. Utilizing 455 nm blue light to excite nitroarenes and enhance their electrophilicity, the method efficiently constructs C–O bonds via an SNAr reaction between nitroarenes and phenolic compounds under mild alkaline conditions. This approach eliminates the need for transition metals, operates at room temperature under mild conditions, exhibits broad substrate scope, and offers simple operation, thereby providing a green and efficient new pathway for diaryl ether synthesis.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"191 ","pages":"Article 135067"},"PeriodicalIF":2.2,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733909","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-02DOI: 10.1016/j.tet.2025.135074
Laiba Anwar , Sajjad Ahmad , Kulsoom Ghulam Ali , Bushra Parveen , Ameer Fawad Zahoor , Syed Ali Raza Naqvi , Jaweriya Ashraf , Usman Nazeer
The Stille coupling reaction has garnered significant interest as an innovative approach for forming carbon-carbon bonds due to its broad substrate scope and the stability of organotin compounds. Traditionally reliant on palladium-based homogeneous catalysis, recent developments have explored heterogeneous catalytic systems that utilize transition metals and their nanoparticles to enhance sustainability, cost-effectiveness and ease of recovery. Metal-based nanoparticles (Pd, Au and Cu) with high surface-to-volume ratio and excellent catalytic activity offer various advantages including enhanced thermal stability, reduced metal leaching, facile catalyst recovery and reusability in heterogeneous catalysis. The Stille reaction has also been extensively employed in the synthesis of natural products. This review summarizes the recent advancements in metallic systems and their nanoparticles-mediated Stille coupling reactions covering literature from 2015 to 2025. Moreover, relevant reaction mechanisms and applications have also been discussed.
{"title":"Recent synthetic innovations in Stille coupling reaction: A review","authors":"Laiba Anwar , Sajjad Ahmad , Kulsoom Ghulam Ali , Bushra Parveen , Ameer Fawad Zahoor , Syed Ali Raza Naqvi , Jaweriya Ashraf , Usman Nazeer","doi":"10.1016/j.tet.2025.135074","DOIUrl":"10.1016/j.tet.2025.135074","url":null,"abstract":"<div><div>The Stille coupling reaction has garnered significant interest as an innovative approach for forming carbon-carbon bonds due to its broad substrate scope and the stability of organotin compounds. Traditionally reliant on palladium-based homogeneous catalysis, recent developments have explored heterogeneous catalytic systems that utilize transition metals and their nanoparticles to enhance sustainability, cost-effectiveness and ease of recovery. Metal-based nanoparticles (Pd, Au and Cu) with high surface-to-volume ratio and excellent catalytic activity offer various advantages including enhanced thermal stability, reduced metal leaching, facile catalyst recovery and reusability in heterogeneous catalysis. The Stille reaction has also been extensively employed in the synthesis of natural products. This review summarizes the recent advancements in metallic systems and their nanoparticles-mediated Stille coupling reactions covering literature from 2015 to 2025. Moreover, relevant reaction mechanisms and applications have also been discussed.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"191 ","pages":"Article 135074"},"PeriodicalIF":2.2,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.tet.2025.135086
Upma Gulati , Anjali Gupta, Joydev K. Laha
A classical transformation involving benzylic oxidation is developed using a metal-free approach. Unlike the reported methods, this report unveils for the first time the synthesis of arylglyoxylic esters from arylacetic esters utilizing the TBN/NHS catalytic system. A variety of substrates in moderate to good yields (up to 85 %) are synthesized to exhibit the practical applicability of the reaction. The synthesized products display great utility and value in terms of synthetic transformations including the synthesis of many useful scaffolds. Mechanistic studies reveal the formation of a benzylic functionalized nitro compound as active intermediate leading to the formation of desired product.
{"title":"Tuning the reactivity of benzylic radicals by virtue of the presence of an acid/ester functional group at the benzylic carbon","authors":"Upma Gulati , Anjali Gupta, Joydev K. Laha","doi":"10.1016/j.tet.2025.135086","DOIUrl":"10.1016/j.tet.2025.135086","url":null,"abstract":"<div><div>A classical transformation involving benzylic oxidation is developed using a metal-free approach. Unlike the reported methods, this report unveils for the first time the synthesis of arylglyoxylic esters from arylacetic esters utilizing the TBN/NHS catalytic system. A variety of substrates in moderate to good yields (up to 85 %) are synthesized to exhibit the practical applicability of the reaction. The synthesized products display great utility and value in terms of synthetic transformations including the synthesis of many useful scaffolds. Mechanistic studies reveal the formation of a benzylic functionalized nitro compound as active intermediate leading to the formation of desired product.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"191 ","pages":"Article 135086"},"PeriodicalIF":2.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01DOI: 10.1016/j.tet.2025.135085
Irina Yu. Krasnova, Nina V. Kuchkina, Elena S. Chamkina, Dmitry Yu. Antonov, Alexandr A. Chamkin, Zinaida B. Shifrina
A series of ferrocenyl-functionalized dendrons were synthesized as model precursors for redox-active Janus dendrimers with rigid rylene chromophore cores. Azidoferrocenes incorporating methylene, hexyl, or undecyl spacers were obtained via acylation–reduction–azidation sequences and subsequently conjugated to phenylene-based ethynyl dendrons through Cu(I)-catalyzed azide–alkyne cycloaddition, affording dendritic architectures with high structural definition. Comprehensive characterization by NMR spectroscopy and MALDI-ToF mass spectrometry confirmed the successful incorporation of ferrocenyl termini. Cyclic voltammetry revealed a single, chemically reversible one-electron oxidation wave for all compounds, consistent with non-interacting ferrocenyl sites. For dendrons bearing extended alkyl linkers (7, 7 N, 8, 8 N), the redox processes were fully reversible and diffusion-controlled, in agreement with efficient intramolecular electron transfer (electron-hopping). In contrast, dendrons with short methylene spacers (6, 6 N) exhibited broadened voltammetric profiles and increased ΔEp at high scan rates, indicative of hindered charge transfer kinetics imposed by proximal triazole groups. Pyridyl substitution had negligible electronic effects but imparted tunable solubility. These findings establish clear structure–redox correlations and provide a robust foundation for the future construction of multifunctional Janus dendrimers integrating ferrocenyl dendrons with rylene-based fluorescent and photothermal cores.
合成了一系列二茂铁功能化的树突，作为具有刚性乙烯发色团核的氧化还原活性Janus树突的模型前体。通过酰化-还原-叠氮化序列得到含有亚甲基、己基或十一基间隔物的叠氮二茂化合物，随后通过Cu(I)催化叠氮-炔环加成与苯基乙基树突结合，形成具有高结构清晰度的树突结构。通过核磁共振光谱和MALDI-ToF质谱综合表征证实了二茂铁末端的成功结合。循环伏安法显示，所有化合物都有一个化学可逆的单电子氧化波，与非相互作用的二茂铁基位点一致。对于含有扩展烷基连接体（7,7 N, 8,8 N）的树突，氧化还原过程是完全可逆和扩散控制的，与有效的分子内电子转移（电子跳迁）一致。相比之下，具有短亚甲基间隔物（6,6 N）的树突在高扫描速率下表现出宽的伏安谱和增加的ΔEp，表明近端三唑基团施加的电荷转移动力学受到阻碍。吡啶基取代的电子效应可以忽略不计，但其溶解度可调。这些发现建立了清晰的结构-氧化还原相关性，并为未来构建将二茂铁树突与乙烯基荧光和光热核结合的多功能Janus树突提供了坚实的基础。
{"title":"Ferrocene terminated aromatic dendrons for the construction of Janus dendrimers. Synthesis and electrochemical study","authors":"Irina Yu. Krasnova, Nina V. Kuchkina, Elena S. Chamkina, Dmitry Yu. Antonov, Alexandr A. Chamkin, Zinaida B. Shifrina","doi":"10.1016/j.tet.2025.135085","DOIUrl":"10.1016/j.tet.2025.135085","url":null,"abstract":"<div><div>A series of ferrocenyl-functionalized dendrons were synthesized as model precursors for redox-active Janus dendrimers with rigid rylene chromophore cores. Azidoferrocenes incorporating methylene, hexyl, or undecyl spacers were obtained via acylation–reduction–azidation sequences and subsequently conjugated to phenylene-based ethynyl dendrons through Cu(I)-catalyzed azide–alkyne cycloaddition, affording dendritic architectures with high structural definition. Comprehensive characterization by NMR spectroscopy and MALDI-ToF mass spectrometry confirmed the successful incorporation of ferrocenyl termini. Cyclic voltammetry revealed a single, chemically reversible one-electron oxidation wave for all compounds, consistent with non-interacting ferrocenyl sites. For dendrons bearing extended alkyl linkers (7, 7 N, 8, 8 N), the redox processes were fully reversible and diffusion-controlled, in agreement with efficient intramolecular electron transfer (electron-hopping). In contrast, dendrons with short methylene spacers (6, 6 N) exhibited broadened voltammetric profiles and increased ΔEp at high scan rates, indicative of hindered charge transfer kinetics imposed by proximal triazole groups. Pyridyl substitution had negligible electronic effects but imparted tunable solubility. These findings establish clear structure–redox correlations and provide a robust foundation for the future construction of multifunctional Janus dendrimers integrating ferrocenyl dendrons with rylene-based fluorescent and photothermal cores.</div></div>","PeriodicalId":437,"journal":{"name":"Tetrahedron","volume":"191 ","pages":"Article 135085"},"PeriodicalIF":2.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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