Pub Date : 2025-12-16DOI: 10.1016/j.tetlet.2025.155933
Guiyun Tang , Kai Li , Xingdan Wang , Shuo Mu , Yuanming Lv , Qidi Zhong , Huanhuan Jiang , Zhiqiang Xie
Herein, we describe a visible-light-induced, TEMPO-mediated radical cyclization strategy for the efficient synthesis of indolizine derivatives from 3-cyano-1,4-dihydropyridine substrates. This metal- and base-free protocol proceeds under ambient conditions, affording the target products in good yields with broad functional group tolerance. The method features a simple setup, low energy consumption, and mild reaction conditions, offering a practical and environmentally benign route to access this important class of indolizine derivatives.
{"title":"Visible-light-induced direct synthesis of indolizine derivatives via radical cyclization of 3-cyano-1,4-dihydropyridine compounds","authors":"Guiyun Tang , Kai Li , Xingdan Wang , Shuo Mu , Yuanming Lv , Qidi Zhong , Huanhuan Jiang , Zhiqiang Xie","doi":"10.1016/j.tetlet.2025.155933","DOIUrl":"10.1016/j.tetlet.2025.155933","url":null,"abstract":"<div><div>Herein, we describe a visible-light-induced, TEMPO-mediated radical cyclization strategy for the efficient synthesis of indolizine derivatives from 3-cyano-1,4-dihydropyridine substrates. This metal- and base-free protocol proceeds under ambient conditions, affording the target products in good yields with broad functional group tolerance. The method features a simple setup, low energy consumption, and mild reaction conditions, offering a practical and environmentally benign route to access this important class of indolizine derivatives.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"176 ","pages":"Article 155933"},"PeriodicalIF":1.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-16DOI: 10.1016/j.tetlet.2025.155930
Yongchun Gao , Xi Yang , Liqin Wang
Four undescribed ent-labdane diterpenes, caesldecapins A–D (1–4), along with four artificial or known ent-labdane diterpenes (5–8) were isolated from the twigs and leaves of Caesalpinia decapetala. Their structures were elucidated by extensive spectroscopic analyses, including HRMS, 1D and 2D NMR spectral data. Caesldecapin D (4) was a rare 2,3:3,4-diseco-3,19-dinor-ent-labdane diterpene.
从十足杉（Caesalpinia decaptala）的细枝和叶片中分离得到4个未描述的邻边丹二萜，caesldecapins A-D（1-4）和4个人工或已知的邻边丹二萜（5-8）。它们的结构通过广泛的光谱分析，包括HRMS， 1D和2D NMR光谱数据来阐明。该二萜是一种罕见的2,3:3,4- diso -3,19-dinor- ant -labdane二萜。
{"title":"Ent-labdane diterpenoids including a rare 3,19-dinor-ent-labdane from Caesalpinia decapetala Alston","authors":"Yongchun Gao , Xi Yang , Liqin Wang","doi":"10.1016/j.tetlet.2025.155930","DOIUrl":"10.1016/j.tetlet.2025.155930","url":null,"abstract":"<div><div>Four undescribed <em>ent</em>-labdane diterpenes, caesldecapins A–D (<strong>1–4</strong>), along with four artificial or known <em>ent</em>-labdane diterpenes (<strong>5</strong>–<strong>8</strong>) were isolated from the twigs and leaves of <em>Caesalpinia decapetala.</em> Their structures were elucidated by extensive spectroscopic analyses, including HRMS, 1D and 2D NMR spectral data. Caesldecapin D (<strong>4</strong>) was a rare 2,3:3,4-diseco-3,19-dinor-<em>ent</em>-labdane diterpene.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"176 ","pages":"Article 155930"},"PeriodicalIF":1.5,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-14DOI: 10.1016/j.tetlet.2025.155931
Ivan A. Kochnev, Alexey Y. Barkov
In this work we demonstrate the regio- and diastereoselective transformation of 2-substituted-3-nitro-2H-chromenes to cyclopenta[c]chromenes. The synthesis of cyclopenta[c]chromenes based on phosphine-catalyzed [3+2] allene cycloaddition reaction in chloroform. The effect of substituents on the C-2 atom of 3-nitro-2H-chormene was demonstrated. This convenient and simple method allows obtaining functionalized cyclopenta[c]chromenes with yields up to 82 %. Moreover, this protocol has been successfully used in the synthesis of series of trifluoromethyl-containing products, without changing regio- and stereoselectivity of the reaction.
{"title":"Diastereoselective annulation of 2-substituted 3-nitro-2H-chromenes by phosphine catalyzed [3+2] allenoate cycloaddition: Syntheses of tetrahydrocyclopenta[c]chromenes","authors":"Ivan A. Kochnev, Alexey Y. Barkov","doi":"10.1016/j.tetlet.2025.155931","DOIUrl":"10.1016/j.tetlet.2025.155931","url":null,"abstract":"<div><div>In this work we demonstrate the regio- and diastereoselective transformation of 2-substituted-3-nitro-2<em>H</em>-chromenes to cyclopenta[<em>c</em>]chromenes. The synthesis of cyclopenta[<em>c</em>]chromenes based on phosphine-catalyzed [3+2] allene cycloaddition reaction in chloroform. The effect of substituents on the C-2 atom of 3-nitro-2<em>H</em>-chormene was demonstrated. This convenient and simple method allows obtaining functionalized cyclopenta[<em>c</em>]chromenes with yields up to 82 %. Moreover, this protocol has been successfully used in the synthesis of series of trifluoromethyl-containing products, without changing regio- and stereoselectivity of the reaction.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"176 ","pages":"Article 155931"},"PeriodicalIF":1.5,"publicationDate":"2025-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145789151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-13DOI: 10.1016/j.tetlet.2025.155920
Xuejiao Chen , Wenqing Luo , Zhibin Zhang , Yufeng Liu , Yalin Zhang , Guoping Yang
This study presents an efficient and environmentally benign protocol for the synthesis of quinazolinones via H3PW12O40-catalyzed cyclization of o-aminobenzamides with ortho esters under mild conditions. By employing H3PW12O40 as the catalyst and EtOH as the solvent, various o-aminobenzamides and ortho esters reacted efficiently to form quinazolinones up to 96 % yield. The advantages of this transformation include the use of a green catalyst and solvent, a broad substrate scope, high efficiency, and operational simplicity. This strategy would provide opportunities for the green synthesis of potential biologically active molecules.
{"title":"H3PW12O40-catalyzed cyclization of o-aminobenzamides with ortho esters for quinazolinones synthesis","authors":"Xuejiao Chen , Wenqing Luo , Zhibin Zhang , Yufeng Liu , Yalin Zhang , Guoping Yang","doi":"10.1016/j.tetlet.2025.155920","DOIUrl":"10.1016/j.tetlet.2025.155920","url":null,"abstract":"<div><div>This study presents an efficient and environmentally benign protocol for the synthesis of quinazolinones via H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub>-catalyzed cyclization of <em>o</em>-aminobenzamides with <em>ortho</em> esters under mild conditions. By employing H<sub>3</sub>PW<sub>12</sub>O<sub>40</sub> as the catalyst and EtOH as the solvent, various <em>o</em>-aminobenzamides and <em>ortho</em> esters reacted efficiently to form quinazolinones up to 96 % yield. The advantages of this transformation include the use of a green catalyst and solvent, a broad substrate scope, high efficiency, and operational simplicity. This strategy would provide opportunities for the green synthesis of potential biologically active molecules.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155920"},"PeriodicalIF":1.5,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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.tetlet.2025.155927
Kunal Madaan, Ram Singh
In this work, we have reported the synthesis of 3-hydroxy-3-acylisoinolin-1-ones from 2-(1-alkynyl)benzamides mediated by Selectfluor. This facile and novel methodology affords various 3-hydroxy-3-acylisoinolin-1-ones with yields of 73–85 % in 5 h. In this method, cyclization, oxidation, and hydroxylation of 2-(1-alkynyl)benzamides takes place in one pot single step. Control experiments were performed to understand and propose the mechanism of this novel synthetic route.
{"title":"Selectfluor-mediated regioselective synthesis of 3-Hydroxy-3-acylisoinolin-1-ones from 2-(1-alkynyl)benzamides","authors":"Kunal Madaan, Ram Singh","doi":"10.1016/j.tetlet.2025.155927","DOIUrl":"10.1016/j.tetlet.2025.155927","url":null,"abstract":"<div><div>In this work, we have reported the synthesis of 3-hydroxy-3-acylisoinolin-1-ones from 2-(1-alkynyl)benzamides mediated by Selectfluor. This facile and novel methodology affords various 3-hydroxy-3-acylisoinolin-1-ones with yields of 73–85 % in 5 h. In this method, cyclization, oxidation, and hydroxylation of 2-(1-alkynyl)benzamides takes place in one pot single step. Control experiments were performed to understand and propose the mechanism of this novel synthetic route.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155927"},"PeriodicalIF":1.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A general method for preparing spirocyclic/cyclic tetraarylmethanes through one-step cyclization of diaryl compounds (diaryl, diarylamine, diaryl ether, and diaryl thioether) with diarylketones using triflimide (HNTf₂) as a catalyst has been developed. The key step involves a Friedel-Crafts reaction. This straightforward synthetic approach features wide substrate scope, mild reaction conditions, a low catalyst amount, good yield, and allows the synthesis of unusual spirocyclic compounds that are otherwise difficult to achieve.
{"title":"A general cyclization strategy of diaryl, diarylamine, diaryl ether, and diaryl thioether with diarylketone: one-step synthesis of spirocyclic/ cyclic tetraarylmethanes","authors":"Shuangping Liao , Yeshen Liu , Bochao Jiang , Yufeng Hui, Haibo Xiao","doi":"10.1016/j.tetlet.2025.155929","DOIUrl":"10.1016/j.tetlet.2025.155929","url":null,"abstract":"<div><div>A general method for preparing spirocyclic/cyclic tetraarylmethanes through one-step cyclization of diaryl compounds (diaryl, diarylamine, diaryl ether, and diaryl thioether) with diarylketones using triflimide (HNTf₂) as a catalyst has been developed. The key step involves a Friedel-Crafts reaction. This straightforward synthetic approach features wide substrate scope, mild reaction conditions, a low catalyst amount, good yield, and allows the synthesis of unusual spirocyclic compounds that are otherwise difficult to achieve.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"176 ","pages":"Article 155929"},"PeriodicalIF":1.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145754031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A highly diastereoselective synthesis of 3-phthalimido-substituted cis-β-lactam through an ynimide-Kinugasa reaction is reported. This transformation is noteworthy because it offers straightforward access to 3-amino-substituted cis-β-lactams. These compounds are otherwise difficult to obtain: the ynamide–Kinugasa reaction requires harsh deprotection conditions, whereas the Staudinger ketene–imine cycloaddition predominantly furnishes trans-β-lactams.
{"title":"Regio- and stereoselective synthesis of cis-3-amino-β-lactams","authors":"Noriko Okamoto, Chie Nakamo, Keiji Konishi, Takuya Sueda","doi":"10.1016/j.tetlet.2025.155926","DOIUrl":"10.1016/j.tetlet.2025.155926","url":null,"abstract":"<div><div>A highly diastereoselective synthesis of 3-phthalimido-substituted <em>cis</em>-β-lactam through an ynimide-Kinugasa reaction is reported. This transformation is noteworthy because it offers straightforward access to 3-amino-substituted <em>cis</em>-β-lactams. These compounds are otherwise difficult to obtain: the ynamide–Kinugasa reaction requires harsh deprotection conditions, whereas the Staudinger ketene–imine cycloaddition predominantly furnishes <em>trans</em>-β-lactams.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155926"},"PeriodicalIF":1.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An unprecedented 1,6 conjugate addition of aza-nucleophile indoline to 4-nitro-5-styrylisoxazoles is reported. Selected adducts, which were obtained in high yields, were subsequently converted to the corresponding β-indolinecarboxylates via the hydrolysis of the 4-nitroisoxazole core. The synthetic methodology, herein described, provides access to indoline-beta carboxylic acids and their esters which synthesis has been rarely reported.
{"title":"The reaction of 4-nitro-5-styrylisoxazoles and indoline","authors":"Simone Bruschi , Lucio Leopaldi , Erica Paltrinieri , Mauro F.A. Adamo","doi":"10.1016/j.tetlet.2025.155925","DOIUrl":"10.1016/j.tetlet.2025.155925","url":null,"abstract":"<div><div>An unprecedented 1,6 conjugate addition of aza-nucleophile indoline to 4-nitro-5-styrylisoxazoles is reported. Selected adducts, which were obtained in high yields, were subsequently converted to the corresponding β-indolinecarboxylates via the hydrolysis of the 4-nitroisoxazole core. The synthetic methodology, herein described, provides access to indoline-beta carboxylic acids and their esters which synthesis has been rarely reported.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155925"},"PeriodicalIF":1.5,"publicationDate":"2025-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-06DOI: 10.1016/j.tetlet.2025.155923
Bingbing Hou , Shengnan Zhang , Jiajing Su , Fangyi Gong , Wenke Sun , Longjun Ma , Hongxin Liu
Herein, we have developed a novel, environmentally friendly, straightforward, and practical methodology for the construction of 1,3-dihydroxy lactams incorporating multiple quaternary carbon centers through cascade reactions between ketoamides and acetyl compounds in aqueous media. Such molecular architectures are prevalent in natural product systems. This transformation constitutes the first reported instance of employing an amino acid salt to catalyze the formation of dihydroxy lactam-fused polycyclic quaternary carbon frameworks via a sequential aldol and azo-aldol addition cascade process in an aqueous environment. Notably, this reaction exhibits exceptional atom economy, facilitates gram-scale synthesis, and enables multiple catalytic turnovers, delivering the desired products in excellent yields and diastereoselectivities with convenient isolation via centrifugation.
{"title":"Aqueous-phase construction of dihydroxy lactam via cascade reaction catalyzed by amino acid salts","authors":"Bingbing Hou , Shengnan Zhang , Jiajing Su , Fangyi Gong , Wenke Sun , Longjun Ma , Hongxin Liu","doi":"10.1016/j.tetlet.2025.155923","DOIUrl":"10.1016/j.tetlet.2025.155923","url":null,"abstract":"<div><div>Herein, we have developed a novel, environmentally friendly, straightforward, and practical methodology for the construction of 1,3-dihydroxy lactams incorporating multiple quaternary carbon centers through cascade reactions between ketoamides and acetyl compounds in aqueous media. Such molecular architectures are prevalent in natural product systems. This transformation constitutes the first reported instance of employing an amino acid salt to catalyze the formation of dihydroxy lactam-fused polycyclic quaternary carbon frameworks <em>via</em> a sequential aldol and azo-aldol addition cascade process in an aqueous environment. Notably, this reaction exhibits exceptional atom economy, facilitates gram-scale synthesis, and enables multiple catalytic turnovers, delivering the desired products in excellent yields and diastereoselectivities with convenient isolation <em>via</em> centrifugation.</div></div>","PeriodicalId":438,"journal":{"name":"Tetrahedron Letters","volume":"175 ","pages":"Article 155923"},"PeriodicalIF":1.5,"publicationDate":"2025-12-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145733303","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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