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Nucleophilic Substitution at Unactivated Arene C–H: Copper-Catalyzed anti-Selective Silylative Cyclization of Substituted Benzylacetylenes
IF 5.2 1区 化学
Organic Letters Pub Date : 2025-02-13 DOI: 10.1021/acs.orglett.5c00323
Hirokazu Moniwa, Ryo Shintani
{"title":"Nucleophilic Substitution at Unactivated Arene C–H: Copper-Catalyzed anti-Selective Silylative Cyclization of Substituted Benzylacetylenes","authors":"Hirokazu Moniwa, Ryo Shintani","doi":"10.1021/acs.orglett.5c00323","DOIUrl":"https://doi.org/10.1021/acs.orglett.5c00323","url":null,"abstract":"A new mode of carbon–carbon bond formation via electrophilic activation of a C–H bond has been developed in the context of a copper-catalyzed <i>anti</i>-selective silylative cyclization of benzylacetylenes with silylboronates for the synthesis of 2-silyl-1<i>H</i>-indenes. The reaction proceeds with high regioselectivity for various substituted benzylacetylenes, and the resulting products could be further functionalized. The arene that undergoes cyclization acts as an electrophile with the release of hydride under redox neutral conditions, and the reaction mechanism was probed by the deuterium-labeling experiments and the density functional theory calculations.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"8 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401632","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}
引用次数: 0
Stereoselective Intramolecular Oxypalladation of Cyclic 1,3-Dione-Tethered Alkynes
IF 4.9 1区 化学
Organic Letters Pub Date : 2025-02-13 DOI: 10.1021/acs.orglett.5c0010610.1021/acs.orglett.5c00106
Lakshmi Revati Magham, Abdus Samad, Anandarao Munakala and Rambabu Chegondi*, 
{"title":"Stereoselective Intramolecular Oxypalladation of Cyclic 1,3-Dione-Tethered Alkynes","authors":"Lakshmi Revati Magham,&nbsp;Abdus Samad,&nbsp;Anandarao Munakala and Rambabu Chegondi*,&nbsp;","doi":"10.1021/acs.orglett.5c0010610.1021/acs.orglett.5c00106","DOIUrl":"https://doi.org/10.1021/acs.orglett.5c00106https://doi.org/10.1021/acs.orglett.5c00106","url":null,"abstract":"<p >An unconventional, highly stereoselective, and regioselective intramolecular oxypalladation/acyloxylation cascade of alkyne-tethered cyclic 1,3-diones has been developed. This atom-economic Pd(II)-catalyzed annulation reaction is initiated by the oxypalladation of alkyne with an internal carbonyl group via 5-<i>exo</i>-<i>dig</i> cyclization instead of the conventional acetoxypalladation pathway. In this process, the carboxylic acid plays a pivotal role in the generation of an active cationic Pd–complex and the subsequent acyloxylation and proto-demetalation steps. Additionally, this method enables asymmetric cyclization using a chiral bidentate BOX ligand, achieving enantiomeric ratios of ≤93:7.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 7","pages":"1700–1705 1700–1705"},"PeriodicalIF":4.9,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452403","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}
引用次数: 0
Nucleophilic Substitution at Unactivated Arene C–H: Copper-Catalyzed anti-Selective Silylative Cyclization of Substituted Benzylacetylenes
IF 4.9 1区 化学
Organic Letters Pub Date : 2025-02-13 DOI: 10.1021/acs.orglett.5c0032310.1021/acs.orglett.5c00323
Hirokazu Moniwa,  and , Ryo Shintani*, 
{"title":"Nucleophilic Substitution at Unactivated Arene C–H: Copper-Catalyzed anti-Selective Silylative Cyclization of Substituted Benzylacetylenes","authors":"Hirokazu Moniwa,&nbsp; and ,&nbsp;Ryo Shintani*,&nbsp;","doi":"10.1021/acs.orglett.5c0032310.1021/acs.orglett.5c00323","DOIUrl":"https://doi.org/10.1021/acs.orglett.5c00323https://doi.org/10.1021/acs.orglett.5c00323","url":null,"abstract":"<p >A new mode of carbon–carbon bond formation via electrophilic activation of a C–H bond has been developed in the context of a copper-catalyzed <i>anti</i>-selective silylative cyclization of benzylacetylenes with silylboronates for the synthesis of 2-silyl-1<i>H</i>-indenes. The reaction proceeds with high regioselectivity for various substituted benzylacetylenes, and the resulting products could be further functionalized. The arene that undergoes cyclization acts as an electrophile with the release of hydride under redox neutral conditions, and the reaction mechanism was probed by the deuterium-labeling experiments and the density functional theory calculations.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 7","pages":"1763–1768 1763–1768"},"PeriodicalIF":4.9,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452402","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}
引用次数: 0
Stereoselective Intramolecular Oxypalladation of Cyclic 1,3-Dione-Tethered Alkynes
IF 5.2 1区 化学
Organic Letters Pub Date : 2025-02-13 DOI: 10.1021/acs.orglett.5c00106
Lakshmi Revati Magham, Abdus Samad, Anandarao Munakala, Rambabu Chegondi
{"title":"Stereoselective Intramolecular Oxypalladation of Cyclic 1,3-Dione-Tethered Alkynes","authors":"Lakshmi Revati Magham, Abdus Samad, Anandarao Munakala, Rambabu Chegondi","doi":"10.1021/acs.orglett.5c00106","DOIUrl":"https://doi.org/10.1021/acs.orglett.5c00106","url":null,"abstract":"An unconventional, highly stereoselective, and regioselective intramolecular oxypalladation/acyloxylation cascade of alkyne-tethered cyclic 1,3-diones has been developed. This atom-economic Pd(II)-catalyzed annulation reaction is initiated by the oxypalladation of alkyne with an internal carbonyl group via 5-<i>exo</i>-<i>dig</i> cyclization instead of the conventional acetoxypalladation pathway. In this process, the carboxylic acid plays a pivotal role in the generation of an active cationic Pd–complex and the subsequent acyloxylation and proto-demetalation steps. Additionally, this method enables asymmetric cyclization using a chiral bidentate BOX ligand, achieving enantiomeric ratios of ≤93:7.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"30 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401630","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}
引用次数: 0
Rh-Catalyzed Formal [3 + 2] Cycloaddition Reactions with Cyclopropenones via Sequential C-H/C-C Bond Activation.
IF 4.9 1区 化学
Organic Letters Pub Date : 2025-02-13 DOI: 10.1021/acs.orglett.5c00248
Qing-Long Qu, Yu-Tong Ren, Jun-Tao Cao, Wei Sun, Meng Sun
{"title":"Rh-Catalyzed Formal [3 + 2] Cycloaddition Reactions with Cyclopropenones via Sequential C-H/C-C Bond Activation.","authors":"Qing-Long Qu, Yu-Tong Ren, Jun-Tao Cao, Wei Sun, Meng Sun","doi":"10.1021/acs.orglett.5c00248","DOIUrl":"https://doi.org/10.1021/acs.orglett.5c00248","url":null,"abstract":"<p><p>The utilization of high-valent metal catalysts to promote cycloaddition reactions involving π bonds through C-C bond activation remains challenging. Despite extensive research, the cycloaddition of aldehydes with cyclopropenones catalyzed by metal complexes has not been documented. Herein, we disclose a novel Rh(III)-catalyzed cycloaddition reaction between cyclopropenones and aldehydes, enabling the efficient synthesis of highly functionalized furanones. A detailed mechanistic investigation was conducted, revealing the likely involvement of a tripodal Rh-carbene intermediate in the catalytic cycle, which facilitates the product release pathway. This reaction exhibits a broad substrate scope, good functional group compatibility, and high atom economy, thereby offering a versatile and general approach to the construction of furanones.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":" ","pages":""},"PeriodicalIF":4.9,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143412401","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}
引用次数: 0
Modular Construction of Chiral Aminopiperidine via Palladium-Catalyzed Hydroamination of 1,2-Dihydropyridine
IF 5.2 1区 化学
Organic Letters Pub Date : 2025-02-12 DOI: 10.1021/acs.orglett.4c04736
Qian Wang, Shunshun Huang, Lifei Nie, Jiangyu Zhao, Haji Akber Aisa, Liyin Jiang
{"title":"Modular Construction of Chiral Aminopiperidine via Palladium-Catalyzed Hydroamination of 1,2-Dihydropyridine","authors":"Qian Wang, Shunshun Huang, Lifei Nie, Jiangyu Zhao, Haji Akber Aisa, Liyin Jiang","doi":"10.1021/acs.orglett.4c04736","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04736","url":null,"abstract":"In this study, we describe a generally straightforward methodology for the catalytic synthesis of chiral aminopiperidine from pyridine and azoles. The key step was the palladium-catalyzed regioselective N–H insertion into the double bond of 1,2-dihydropyridine. This hydroamination exhibits a wide substrate scope and functional group compatibility. Mechanistic study revealed that the catalytic N–H insertion into the C═C bond followed <i>cis</i> addition. The utility of this protocol was demonstrated by diverse functionalization of the enamine double bond.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"41 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401633","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}
引用次数: 0
Macrocyclic Decanor- (C15) and Pentanor- (C20) Sesterterpenoids and C25 Precursor with Immunosuppressive Activity from Leucosceptrum canum
IF 5.2 1区 化学
Organic Letters Pub Date : 2025-02-12 DOI: 10.1021/acs.orglett.4c04812
Xiao-Ping He, Xin Yuan, Ting-Ting Zhou, Kai Guo, Shi-Ming Chen, Yun Wang, Rong-Fang Mu, Jing Chen, Yan Liu, Sheng-Hong Li
{"title":"Macrocyclic Decanor- (C15) and Pentanor- (C20) Sesterterpenoids and C25 Precursor with Immunosuppressive Activity from Leucosceptrum canum","authors":"Xiao-Ping He, Xin Yuan, Ting-Ting Zhou, Kai Guo, Shi-Ming Chen, Yun Wang, Rong-Fang Mu, Jing Chen, Yan Liu, Sheng-Hong Li","doi":"10.1021/acs.orglett.4c04812","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04812","url":null,"abstract":"Phytochemical investigation on the leaves of <i>Leucosceptrum canum</i> led to the discovery of leucosceptrone A (<b>1</b>), a rearranged pentanor-leucosceptrane sesterterpenoid (C<sub>20</sub>) with an unprecedented 6/9/5 tricyclic framework, and leucosceptrones B–E (<b>2</b>–<b>5</b>), three decanor-leucosesterterpane sesterterpenoids (C<sub>15</sub>) and a C<sub>25</sub> biosynthetic precursor with two different unusual 10/5 bicyclic systems. Their structures were elucidated by extensive NMR spectroscopic analysis, quantum-chemical calculations, and X-ray diffraction analysis. A plausible biosynthetic route for these macrocyclic sesterterpenoids was proposed. Compounds <b>1</b> and <b>5</b> exhibited immunosuppressive activity by inhibiting the proliferation of T cells and the production of cytokine IFN-γ, and <b>5</b> was more active, with IC<sub>50</sub> values of 5.00 and 3.06 <i>μ</i>M, respectively.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"208 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143401635","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}
引用次数: 0
Exploring Diazo Compounds for the Divergent Electro-Cascade Sequence and S–H Insertion Reaction
IF 4.9 1区 化学
Organic Letters Pub Date : 2025-02-12 DOI: 10.1021/acs.orglett.4c0467010.1021/acs.orglett.4c04670
Jaswant Kumar, Deepak Sharma, Yaseen Hussain,  Solaim, Jatin Sinhmar,  Muskan, Avtar Changotra* and Pankaj Chauhan*, 
{"title":"Exploring Diazo Compounds for the Divergent Electro-Cascade Sequence and S–H Insertion Reaction","authors":"Jaswant Kumar,&nbsp;Deepak Sharma,&nbsp;Yaseen Hussain,&nbsp; Solaim,&nbsp;Jatin Sinhmar,&nbsp; Muskan,&nbsp;Avtar Changotra* and Pankaj Chauhan*,&nbsp;","doi":"10.1021/acs.orglett.4c0467010.1021/acs.orglett.4c04670","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04670https://doi.org/10.1021/acs.orglett.4c04670","url":null,"abstract":"<p >We have explored the reactivity of diazo compounds under electrochemical conditions to establish a cascade sequence of thiolation/cyclization/reduction reactions. Electrolyzing styryl diazo imides and aryl thiols enables direct access to a single diastereoisomer of 2,5-pyrrolidine-dione-fused thiochromans in good yield under mild and metal-free conditions. Notably, a tunable reactivity has been achieved via S–H insertion at the diazo center in modified reaction conditions. Based on the experimental evidences, including the detection of key intermediates and computational studies, the mechanism for the electrochemical cascade reaction has also been established.</p>","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"27 7","pages":"1608–1613 1608–1613"},"PeriodicalIF":4.9,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143452640","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}
引用次数: 0
Pochobulbins A–F, Immunosuppressive Secopenitrem-Type Indole Diterpenoids from an Endophytic Pochonia bulbillosa 内生蒲公英球茎植物中的免疫抑制性 Secopenitrem 型吲哚二萜类化合物 Pochobulbins A-F
IF 5.2 1区 化学
Organic Letters Pub Date : 2025-02-12 DOI: 10.1021/acs.orglett.5c00291
Chun-Lun Qin, Wan-Peng Li, Xiao-Kun Yu, Zheng Li, Jia-Yun Hu, Yin-Hui Zhou, Han-Li Ruan
{"title":"Pochobulbins A–F, Immunosuppressive Secopenitrem-Type Indole Diterpenoids from an Endophytic Pochonia bulbillosa","authors":"Chun-Lun Qin, Wan-Peng Li, Xiao-Kun Yu, Zheng Li, Jia-Yun Hu, Yin-Hui Zhou, Han-Li Ruan","doi":"10.1021/acs.orglett.5c00291","DOIUrl":"https://doi.org/10.1021/acs.orglett.5c00291","url":null,"abstract":"Three monoclavatol-secopenitrems (<b>1</b>–<b>3</b>), one bis-clavatol-secopenitrem (<b>4</b>), and two bis<b>-</b>5-methylpyrogallol-secopenitrems (<b>5</b> and <b>6</b>) were obtained from the endophytic fungus <i>Pochonia bulbillosa</i> KNI755. Pochobulbins A–F (<b>1</b>–<b>6</b>) are the initial instances of secopenitrem-type indole diterpenoids with a 4/6/6/5/5/6/6/6/6/6 fused decacyclic ring system. Compounds <b>1</b>–<b>4</b> feature a secopenitrem skeleton fused to a clavatol unit via a tetrahydro-2<i>H</i>-pyran bridge. Compounds <b>5</b> and <b>6</b> are the first secopenitrem-type indole diterpenoids that connect a 5-methylpyrogallol unit to a secopenitrem unit via a 1,4-dioxane bridge. The complete structures, including their absolute stereochemical assignments, were determined through comprehensive spectroscopic analyses and ECD simulations. Compounds <b>1</b>, <b>3</b>, and <b>5</b> inhibited T cell proliferation, and compounds <b>1</b> and <b>3</b> also inhibited B cell proliferation, exhibiting EC<sub>50</sub> values between 4.6 and 13 μM.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"129 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393800","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}
引用次数: 0
Exploring Diazo Compounds for the Divergent Electro-Cascade Sequence and S–H Insertion Reaction
IF 5.2 1区 化学
Organic Letters Pub Date : 2025-02-12 DOI: 10.1021/acs.orglett.4c04670
Jaswant Kumar, Deepak Sharma, Yaseen Hussain, Solaim, Jatin Sinhmar, Muskan, Avtar Changotra, Pankaj Chauhan
{"title":"Exploring Diazo Compounds for the Divergent Electro-Cascade Sequence and S–H Insertion Reaction","authors":"Jaswant Kumar, Deepak Sharma, Yaseen Hussain, Solaim, Jatin Sinhmar, Muskan, Avtar Changotra, Pankaj Chauhan","doi":"10.1021/acs.orglett.4c04670","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04670","url":null,"abstract":"We have explored the reactivity of diazo compounds under electrochemical conditions to establish a cascade sequence of thiolation/cyclization/reduction reactions. Electrolyzing styryl diazo imides and aryl thiols enables direct access to a single diastereoisomer of 2,5-pyrrolidine-dione-fused thiochromans in good yield under mild and metal-free conditions. Notably, a tunable reactivity has been achieved via S–H insertion at the diazo center in modified reaction conditions. Based on the experimental evidences, including the detection of key intermediates and computational studies, the mechanism for the electrochemical cascade reaction has also been established.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"18 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393797","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}
引用次数: 0
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