{"title":"DiazaChrysenes (DC): Nitrogen-Containing π-Extended Molecules for Photocatalytic C–H Amination","authors":"Wei Xu, , , Atsushi Iwai, , , Itsuki Nagasaka, , , Satsuki Watanabe, , , Ryosuke Tsutsumi, , and , Naoya Kumagai*, ","doi":"10.1021/acs.orglett.5c03011","DOIUrl":"10.1021/acs.orglett.5c03011","url":null,"abstract":"<p >We report a new class of nitrogen-containing π-extended heterocycles, DiazaChrysenes (<b>DC</b>s), and their dimeric analogues (<b>dDC</b>s) as metal-free photocatalysts for C–H amination. <b>DC</b>s featuring a quinolino[1,2-<i>c</i>]quinazolin-5-ium core were synthesized via electrophilic amide activation and arylation. The resulting compounds displayed tunable photophysical and redox properties, with CF<sub>3</sub>-substituted <b>DC</b>s enabling the C–H amination of arenes with azoles under visible light and aerobic conditions, achieving yields up to 85%. The reaction tolerated a range of arene and azole substrates without requiring metal salts or additives. In contrast, <b>dDC</b>s exhibited diminished activity, likely due to their extended π-curvature. Computational studies, including NCI, ACID, and NICS analyses, revealed locally aromatic but electronically isolated π-systems and deshielded central 8-membered cores. This work highlights the utility of <b>DC</b> scaffolds as synthetically accessible and redox-tunable organic photocatalysts.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 39","pages":"10937–10942"},"PeriodicalIF":5.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145117148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Organic LettersPub Date : 2025-09-22DOI: 10.1021/acs.orglett.5c01697
Samrat Mallick, , , Dipankar Das, , and , Suman De Sarkar*,
{"title":"Stereoselective Electrosynthesis of Imidazolines through Coupling and Ring Restructuring of Alkoxyoxazoles with α-Amino Carbonyls","authors":"Samrat Mallick, , , Dipankar Das, , and , Suman De Sarkar*, ","doi":"10.1021/acs.orglett.5c01697","DOIUrl":"10.1021/acs.orglett.5c01697","url":null,"abstract":"<p >The established strategy unveils metal- and exogenous oxidant-free electrochemical heterocoupling and ring restructuring of alkoxyoxazoles with α-amino carbonyls, furnishing diversely substituted <i>trans</i>-imidazoline scaffolds. This controlled electro-redox coupling and subsequent Brønsted acid-mediated epimerization successfully prevent undesired oxidative aromatization and precisely provide two contiguous stereocenters as a part of the five-membered heterocycle. An extensive range of distinct functionalities is well-tolerated, resulting in a broad substrate scope. Detailed mechanistic investigations enhance the comprehension of the reaction mechanism.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 39","pages":"11111–11116"},"PeriodicalIF":5.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Investigation of the Reactivities of Halogen-Substituted Bicyclic Sialic Acid Donors and Their Application","authors":"Maina Takahashi, , , Sakuma Yasutake, , , Sung-Chi Lin, , , Nanako Nishio, , , Taro Udagawa, , , Hide-Nori Tanaka, , , Akihiro Imamura, , , Hideharu Ishida, , , Cheng-Chung Wang, , , Naoko Komura*, , and , Hiromune Ando*, ","doi":"10.1021/acs.orglett.5c03369","DOIUrl":"10.1021/acs.orglett.5c03369","url":null,"abstract":"<p >We previously developed a fully stereoselective α-sialylation using a macrobicyclic donor. We report that dihalogen substitutions on the macrocyclic moiety greatly enhance the reactivity of macrobicyclic donors. Furthermore, by using Cl- and F-substituted donors, we achieved late-stage regioselective C5 modifications of α(2,8)-linked disialic acids─highly challenging synthetic targets of significant biological importance. This study broadens the utility of the fully stereoselective α-sialylation and underscores the importance of amino group modifications in glycosylation.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 39","pages":"11022–11026"},"PeriodicalIF":5.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145117149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Organoelectrochemistry-Enabled Biomimetic Syntheses of Alstoscholarinoids A and B","authors":"Tong-Ling Cha, , , Chen-Yan Wu, , , Jiang-Li Huang, , , Kun Li, , , Dashan Li, , , Wen-Jing Wang, , and , Li-Dong Shao*, ","doi":"10.1021/acs.orglett.5c03082","DOIUrl":"10.1021/acs.orglett.5c03082","url":null,"abstract":"<p >We report efficient electrochemically enabled syntheses of natural products alstoscholarinoids A (<b>1</b>) and B (<b>2</b>). Employing oleanolic acid (OA) as the feedstock, gram-scale syntheses of biosynthetic precursors diene <b>3</b> (under AP mode) and lactone <b>4</b> (under DC mode) were achieved. Subsequent gram-scale transformations furnished <b>1</b> and <b>2</b> through singlet oxygen-mediated oxidative rearrangement of <b>3</b> and ozonolysis of <b>4</b> followed by an aldol/lactonization cascade, respectively. This strategy delivers <b>1</b> in 36% yield over two steps and <b>2</b> in 42% yield over three steps, establishing the most concise synthetic routes to these architecturally complex triterpenoids to date.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 39","pages":"10943–10947"},"PeriodicalIF":5.0,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145117150","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"4-Nitrophenyl Sulfamates as Precursors Containing Acid-Labile Functional Groups for Sulfamidation with Weakly Nucleophilic Amines","authors":"Fumio Watanabe*, , , Kazuo Hattori, , , Kihito Hada, , , Masaki Tomizawa, , , Toshihiro Aoki, , , Ikumi Hyohdoh, , , Takashi Emura, , and , Kenichi Kawasaki, ","doi":"10.1021/acs.orglett.5c03539","DOIUrl":"10.1021/acs.orglett.5c03539","url":null,"abstract":"<p >We report that 4-nitrophenyl sulfamates readily form sulfamides under mild conditions with a wide range of substrates, including compounds with poorly nucleophilic amino groups and acid-sensitive functional groups that are challenging to prepare via conventional methods. The use of pyridine, a weak base, is key for a clean reaction. The 4-nitrophenyl sulfamates are readily prepared and bench stable, making them valuable for parallel synthesis in medicinal chemistry.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 39","pages":"11100–11104"},"PeriodicalIF":5.0,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Organic LettersPub Date : 2025-09-21DOI: 10.1021/acs.orglett.5c03531
U. Mert Karacaoğlu, and , Yunus E. Türkmen*,
{"title":"Brønsted-Acid-Promoted Diaza-Nazarov Cyclization to Access Tetrasubstituted Pyrazoles","authors":"U. Mert Karacaoğlu, and , Yunus E. Türkmen*, ","doi":"10.1021/acs.orglett.5c03531","DOIUrl":"10.1021/acs.orglett.5c03531","url":null,"abstract":"<p >We have developed a new diaza-Nazarov cyclization for the synthesis of densely substituted pyrazoles. Treatment of <i>N</i>-acylazo substrates with 1–1.5 equiv of trifluoroacetic acid (TFA) as a Brønsted acid promoter at 23 °C afforded hydroxypyrazole products in good to excellent yields (up to 99%). Reactions of substrates with secondary alkyl groups at the β position of the α,β-unsaturated carbonyl moiety gave minor amounts of dihydropyridazinone compounds as side products, proposed to form via an intriguing 6π electrocyclization.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 39","pages":"11094–11099"},"PeriodicalIF":5.0,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/pdf/10.1021/acs.orglett.5c03531","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145093558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Electrochemical β-Scission-Mediated Ring Contraction/Functionalization of 2-Alkylidenecyclobutanol Derivatives","authors":"Haoting Wang, , , Zhiyu Chen, , , Juan Fan, , , Guojuan Liang, , , Qianwen He*, , and , Dong Zhang*, ","doi":"10.1021/acs.orglett.5c03202","DOIUrl":"10.1021/acs.orglett.5c03202","url":null,"abstract":"<p >An electrochemical ring contraction/functionalization of 2-alkylidenecyclobutanol derivatives is presented, enabling the facile and oxidant-free synthesis of β-functionalized cyclopropanecarbaldehydes (CPAs) and cyclopropylketones (CPKs) though anodic oxidation, β-scission, and reoxidation processes. This protocol demonstrates a broad substrate scope, effectively accommodating a diverse range of 2-alkylidenecyclobutanols and various weak nucleophiles, thereby offering straightforward access to β-alkoxylated, hydroxylated, fluorinated, and azidated CPAs. Mechanistic investigations confirm the involvement of a 2-alkylidenecyclobutyl oxy radical intermediate and a subsequent β-scission process.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 39","pages":"10968–10973"},"PeriodicalIF":5.0,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Organic LettersPub Date : 2025-09-21DOI: 10.1021/acs.orglett.5c03332
Wenqian Du, and , Zhonghua Xia*,
{"title":"Gold-Catalyzed Arylative Meyer–Schuster Rearrangement of Aryl Iodides to α-Arylated Enones","authors":"Wenqian Du, and , Zhonghua Xia*, ","doi":"10.1021/acs.orglett.5c03332","DOIUrl":"10.1021/acs.orglett.5c03332","url":null,"abstract":"<p >Enones serve as versatile scaffolds in synthetic chemistry, enabling diverse transformations while exhibiting biologically relevant properties crucial for drug development. Herein, we report a ligand-enabled gold-catalyzed arylative Meyer–Schuster rearrangement employing readily available and stable propargylic acetates and aryl iodides under mild conditions. This method efficiently delivers α-arylated enones with a broad substrate scope and air-tolerant conditions, while avoiding the need for strong external oxidants or photocatalytic activation of aryl diazonium salts.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 39","pages":"11016–11021"},"PeriodicalIF":5.0,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Organic LettersPub Date : 2025-09-21DOI: 10.1021/acs.orglett.5c03211
Sushree Subhasmita Nayak,Aurobindo Patnaik,Chinmay K Jena,Nagendra K Sharma
{"title":"Tropone-Enabled Pd-Catalyzed C(sp2)-H Functionalization of Phenylalanine: Switchable Access to Indoline and Olefinate.","authors":"Sushree Subhasmita Nayak,Aurobindo Patnaik,Chinmay K Jena,Nagendra K Sharma","doi":"10.1021/acs.orglett.5c03211","DOIUrl":"https://doi.org/10.1021/acs.orglett.5c03211","url":null,"abstract":"Herein, we report Pd-catalyzed and site-selective C(sp2)-H amination/olefination of phenylalanine. The transformation proceeds via a troponyl carbonyl-directed intramolecular C-N cyclization forming indoline scaffolds through C(sp2)-H activation with PIDA. In the absence of PIDA, ortho-C(sp2)-H olefination occurs at phenylalanine. This method shows broad substrate scope and excellent functional group tolerance, providing a versatile tool for peptide diversification.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"75 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145103300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Catalyst-Controlled Switchable Mono-/Di-C–H Arylation of Aromatic Amides with Arylsilanes","authors":"Menglong Lu, , , Deyu Wu, , , Tingting Hou, , , Xin Yang, , , Mengmeng Li, , , Wenwu Liu*, , , Heng Xu*, , and , Yi Dong*, ","doi":"10.1021/acs.orglett.5c03239","DOIUrl":"10.1021/acs.orglett.5c03239","url":null,"abstract":"<p >The selective mono/di-C–H arylation of aromatic amides has been developed, enabling efficient coupling with arylsilanes under mild conditions with good functional group tolerance. The regioselectivity (mono- vs diarylation) is catalyst-dependent, with [Cp*RhCl<sub>2</sub>]<sub>2</sub> selectively promoting monoarylation, whereas [Cp*IrCl<sub>2</sub>]<sub>2</sub> demonstrates a distinct preference for diarylation. This approach establishes a straightforward and efficient strategy for the late-stage arylation of pharmaceutical compounds.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 39","pages":"10986–10992"},"PeriodicalIF":5.0,"publicationDate":"2025-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145089699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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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