Lena Deutsch, Lucca Pfitzer, Adam H. Day, Rachel A. Buschmann, Vanessa Raisch, Maximilian Kirchner, Samuel P. Jones, Johannes Kästner, Anke Krueger
{"title":"Synthesis of Flavones by Intramolecular O ‐Arylation of Unactivated Halogenated Aryl‐1,3‐diketones","authors":"Lena Deutsch, Lucca Pfitzer, Adam H. Day, Rachel A. Buschmann, Vanessa Raisch, Maximilian Kirchner, Samuel P. Jones, Johannes Kästner, Anke Krueger","doi":"10.1002/ejoc.70898","DOIUrl":"https://doi.org/10.1002/ejoc.70898","url":null,"abstract":"Flavones are an important class of secondary metabolites in plants. Here we report a straightforward method for the conversion of unactivated halogenated 1,3‐biaryl‐1,3‐diketones into chromenone derivatives via intramolecular <jats:italic>O</jats:italic> ‐arylation under mild conditions. The resulting flavones were obtained in excellent to moderate yields. The synthesis typically proceeds according to a S <jats:sub>N</jats:sub> Ar mechanism under basic conditions without the requirement of any expensive catalyst. After successful implementation of fluorinated aryl diketones which lead to so far inaccessible fluoro‐substituted flavones, the scope of the reaction was also extended to chlorinated and brominated substrates as well as to substances with electron‐withdrawing or ‐donating substituents to demonstrate the functional group tolerance of the method. As an inverted reactivity was observed for bromo‐chloro diketones, quantum chemical calculations have been applied to support the proposed concerted mechanism (cS <jats:sub>N</jats:sub> Ar) for this case.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"6 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149172849","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}
{"title":"Tandem Michael–Aldol Assembly and Regioselective Aminohydroxylation of a Chlorinated Bicyclo[3.3.1]nonane Core Toward Gymnastatin G","authors":"Ly Thi Nguyen, Michael E. Jung, Dong‐Jo Chang","doi":"10.1002/ejoc.70647","DOIUrl":"https://doi.org/10.1002/ejoc.70647","url":null,"abstract":"An efficient and regioselective synthetic approach to the chlorinated bicyclo[3.3.1]nonane core of gymnastatin G is described. The densely functionalized bicyclic framework was assembled via a one‐pot Michael–Aldol cascade followed by silyl protection, enabling simultaneous construction of the bridged skeleton and installation of a bridgehead quaternary chloride with high diastereoselectivity (ca. 9:1 dr). Late‐stage functionalization of the sterically congested bicyclic alkene was achieved through regioselective aminohydroxylation, in which the electronic nature of the <jats:italic>N</jats:italic> ‐oxycarbamate reagent played a critical role in promoting nitrogen incorporation. Systematic variation of the arylsulfonyl group revealed that electron‐deficient substituents significantly enhance reactivity. Attempts to access the corresponding lactone via Baeyer–Villiger rearrangement toward gymnastatin G were unsuccessful, even after modification of the C9 carbonyl, highlighting pronounced steric and stereoelectronic constraints inherent to the rigid [3.3.1] framework. These findings provide insight into the reactivity and functionalization limits of highly substituted bicyclo[3.3.1] systems and offer guidance for future synthetic efforts toward gymnastatin‐type natural products.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"32 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149172843","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}
Man Jiang, Yu‐Mei Ma, Yu Luo, Yu‐Jia Chen, Xing‐Feng Liao, Ze Wang, Jia‐Wei Ruan, Xin Yu, Ying Li, Hai‐Lei Cui
{"title":"POCl 3 /Sulfoxide‐ and Acetyl Bromide/Sulfoxide‐Promoted Oxidative Sulfenylation of Indoles","authors":"Man Jiang, Yu‐Mei Ma, Yu Luo, Yu‐Jia Chen, Xing‐Feng Liao, Ze Wang, Jia‐Wei Ruan, Xin Yu, Ying Li, Hai‐Lei Cui","doi":"10.1002/ejoc.70901","DOIUrl":"https://doi.org/10.1002/ejoc.70901","url":null,"abstract":"A mild and rapid chemoselective sulfenylation of indoles with thiophenols has been established by the employment of sulfoxide as the oxidant and POCl <jats:sub>3</jats:sub> (phosphorus oxychloride) or AcBr (acetyl bromide) as the activator at ambient temperature. Sulfenylation of indoles at the C3 position can be achieved in the presence of POCl <jats:sub>3</jats:sub> and tetramethylene sulfoxide, while a sulfenylation/bromination cascade was reached by combining AcBr and dimethyl sulfoxide in the reaction system.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"10 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149172844","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}
Anthony P. Silvestri, Brady T. Worrell, Aaron W. Feldman
{"title":"Main Group Acetylides in Copper(I)‐Catalyzed Azide–Alkyne Cycloaddition (CuAAC)","authors":"Anthony P. Silvestri, Brady T. Worrell, Aaron W. Feldman","doi":"10.1002/ejoc.70795","DOIUrl":"https://doi.org/10.1002/ejoc.70795","url":null,"abstract":"We report a systematic evaluation of 23 main group (MG) acetylides (Groups 13–17) in CuAAC, confirming prior MG acetylide reports and identifying tin acetylides as novel competent substrates in CuAAC. Optimized protocols for the corresponding triazolides were developed, and 1,4‐regioselectivity was confirmed by single‐crystal X‐ray crystallography. Infrared spectroscopic analysis revealed that alkyne C≡C stretching frequencies decrease systematically upon descending any group, consistent with back‐donation from the heteroatom into the alkyne π*‐orbital and increased electron density at the β‐carbon—features we propose are prerequisites for productive CuAAC. Acetylides of lighter elements (Si, Ge, B) undergo protonolysis under the reaction conditions rather than cycloaddition. Collectively, these results identify metal‐like polarizability as the key criterion governing MG acetylide reactivity in CuAAC and provide a spectroscopic handle for predicting the behavior of heteroatom‐substituted alkynes in this reaction.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"293 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149172846","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}
{"title":"Two‐Phase Electrochemical Vicinal Dibromination of Alkenes With Sodium Bromide as the Bromine Source and Supporting Electrolyte","authors":"Xiaolong Wang, Xuege Su, Lingjie Chen, Qian He","doi":"10.1002/ejoc.70907","DOIUrl":"https://doi.org/10.1002/ejoc.70907","url":null,"abstract":"An environmentally friendly two‐phase electrochemical method for the vicinal dibromination of alkenes has been developed. This strategy utilizes inexpensive sodium bromide as both the bromine source and the supporting electrolyte without the use of catalysts, external oxidants, and strong acids. It features simple operation, mild reaction conditions, broad substrate scope, and high efficiency, affording the desired products in up to 97% yield.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"49 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149172848","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}
Viktor Savic, Dominik Schnalzer, Marko D. Mihovilovic, Michael Schnürch
{"title":"The Expanding Role of Diazirines in Synthetic Methodology","authors":"Viktor Savic, Dominik Schnalzer, Marko D. Mihovilovic, Michael Schnürch","doi":"10.1002/ejoc.70807","DOIUrl":"10.1002/ejoc.70807","url":null,"abstract":"<p>Diazirines are three-membered nitrogen-containing heterocycles best known as photochemical carbene precursors in photoaffinity labeling. Upon irradiation, diazirines undergo nitrogen extrusion to generate highly reactive carbenes capable of covalent bond insertion, a property that has been widely exploited in chemical biology and materials science. Despite their favorable handling properties compared to related diazo compounds and their versatility as both carbene precursors and nitrogen sources, diazirines have historically seen only limited application in synthetic organic chemistry. Over the past two decades, however, diazirines have increasingly emerged as valuable synthons in a broad range of transformations. Their applications can generally be divided into reactions exploiting either their carbene-generating properties or their ability to serve as nitrogen-transfer reagents. Diazirines have been employed in cyclopropanation and cyclopropenation reactions, cross-couplings, skeletal editing, glycosylations, reductive aminations, and the synthesis of nitrogen-containing heterocycles. Owing to their unique reactivity, diazirines can facilitate unusual or otherwise difficult-to-access transformations in organic synthesis. This review provides a comprehensive overview of diazirine-based synthetic methodologies, with particular emphasis on developments reported over the last two decades, and highlights future opportunities for their application in organic synthesis.</p>","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"29 38","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ejoc.70807","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148836296","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pierre Boulay, Fabrice Morlet-Savary, Jean-Michel Becht
{"title":"Synthesis of S-Arylthioxanthonium Trifluoromethanesulfonates From Thioxanthones and Diaryliodonium Salts by Copper(II) Catalysis and Application to Aryl–Heteroaryl Bond Formation by Direct LED Irradiation","authors":"Pierre Boulay, Fabrice Morlet-Savary, Jean-Michel Becht","doi":"10.1002/ejoc.70779","DOIUrl":"10.1002/ejoc.70779","url":null,"abstract":"<p>A short and versatile route to S-arylthioxanthonium trifluoromethanesulfonates via a Cu-catalyzed reaction of diaryliodonium trifluoromethanesulfonates and commercially available thioxanthones is described. Variously substituted S-arylthioxanthonium salts were prepared in only one step from diaryliodonium salts in moderate to good yields. Then, we show one of the first applications of an S-arylthioxanthonium trifluoromethanesulfonate, as an efficient aryl radical precursor by simple and mild direct 365-nm LED irradiation. In preliminary experiments, this aryl radical was successfully trapped with furan without any metallic photocatalyst, thereby enabling the first formation of a new aryl–heteroaryl bond from a sulfonium salt derived from thioxanthone.</p>","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"29 38","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ejoc.70779","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148836199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
María F. Olvera-Granados, Luis A. Polindara-García
{"title":"Synthesis of β- and γ-Carbolinones Through a Fe(III)-Mediated Radical 6-Endo-Trig Cyclization of Indole-Based Ugi 4-CR Adducts","authors":"María F. Olvera-Granados, Luis A. Polindara-García","doi":"10.1002/ejoc.70820","DOIUrl":"10.1002/ejoc.70820","url":null,"abstract":"<p>A novel protocol for Fe(III)-mediated 6-<i>endo-</i>trig radical cyclization of indole-based Ugi 4-CR adducts has been developed, facilitating the synthesis of <i>β</i><i>-</i> and <i>γ</i>-carbolinones via the formation of Fe(III)–H as a key species. This atom-efficient approach proceeds under mild conditions and demonstrates broad functional group tolerance.</p>","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"29 38","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/ejoc.70820","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148893518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chikkappaiahnayaka Santhosh, Kalleshappa Sheela, Kalleshappa Sharath, Maralinganadoddi P. Sadashiva
{"title":"Acid‐Promoted Divergent and Chemoselective Annulation of 2‐(Methylthio)‐2‐Thioxoacetates for the Synthesis of 4‐Oxo‐3,4‐Dihydroquinazolines and 4‐Oxo‐4H‐Benzo[d][1,3]thiazines","authors":"Chikkappaiahnayaka Santhosh, Kalleshappa Sheela, Kalleshappa Sharath, Maralinganadoddi P. Sadashiva","doi":"10.1002/ejoc.70891","DOIUrl":"https://doi.org/10.1002/ejoc.70891","url":null,"abstract":"A divergent and chemoselective method to quinazolinones and benzothiazinones has been developed through the reaction of alkyl/arylmethyl 2‐(methylthio)‐2‐thioxoacetate with 2‐aminobenzamides under Brønsted acid catalysis. The reaction delivered two structurally distinct heterocyclic scaffolds under different reaction conditions from a common synthetic precursor. The use of <jats:italic>p</jats:italic> ‐toluenesulfonic acid ( <jats:italic>p</jats:italic> ‐TSA) in DMF afforded quinazolinone derivatives in good yields, while reactions performed in an AcOH/DMF (1:1) medium produced the corresponding benzothiazinones with excellent chemoselectivity. The methods demonstarte broad applicability under transition metal‐free conditions. The structures and chemoselective cyclization of representative products were unequivocally furnished by spectroscopic characterization and single‐crystal X‐ray diffraction analysis.","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"10 1","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149172965","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}
{"title":"Developing a p-Toluenesulfonic Acid/Benzenesulfonic Acid/Water Mixture as Sustainable Medium for Aqueous Diels–Alder Reactions of Hydrophobic Anthracenes and Various Dienophiles","authors":"Shengyun Hu, Sem Bleus, Shujie Zhao, Wim Dehaen","doi":"10.1002/ejoc.70810","DOIUrl":"10.1002/ejoc.70810","url":null,"abstract":"<p>Aqueous Diels–Alder reactions are highly attractive for green chemistry because of their 100% atom economy and solvent waste mitigation. Despite significant effort, reactions involving hydrophobic dienes and water-sensitive dienophiles, or vice versa, remain challenging. Herein, we implemented an efficient Diels–Alder reaction in a mixture of aqueous <i>p</i>-toluenesulfonic acid and benzenesulfonic acid as a recyclable medium. The methodology features good compatibility with hydrophobic anthracenes and water-sensitive dienophiles, excellent yields, and chromatography-free product isolation. The aqueous medium could easily be recovered and reused multiple times without additional processing.</p>","PeriodicalId":167,"journal":{"name":"European Journal of Organic Chemistry","volume":"29 38","pages":""},"PeriodicalIF":2.8,"publicationDate":"2026-10-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148836298","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}