The regioselective functionalization of the C7 position of quinoline remains a formidable challenge due to its inherent electronic deactivation. Herein, we report an electrochemical strategy that enables divergent synthesis of valuable C7chlorinated and alkylated (arylated) quinolines from simple ortho-propynolaniline precursors. This method leverages electrooxidative dearomatization to generate key cyclohexadienimine intermediates, which undergo two distinct pathways dictated by the para-substituent: TMSCl-mediated cascade chlorination/cyclization delivers 4,7-dichloroquinolines, while substrates bearing para-alkyl/aryl groups (R 2 ≠ Me) undergo an aromatization-driven [1,2]-σ migration to furnish 4-chloro-7-alkyl/arylquinolines with high selectivity. This approach bypasses the reliance on pre-functionalized meta-chloroanilines substrates and hazardous chlorinating agents, operating under mild conditions. Gram-scale synthesis and further derivatizations highlight the practical utility of this method, offering a versatile and sustainable platform for constructing complex quinoline architectures.
{"title":"Electrochemically Enabled C7 Functionalization of Quinolines from o-Propynolanilines: Divergent Access to 4,7-Dichloro and 4-Chloro-7-alkyl (aryl) Quinolines","authors":"Xin Feng, Qiuqin He, Renhua Fan, Jiwen He","doi":"10.1039/d5qo01687h","DOIUrl":"https://doi.org/10.1039/d5qo01687h","url":null,"abstract":"The regioselective functionalization of the C7 position of quinoline remains a formidable challenge due to its inherent electronic deactivation. Herein, we report an electrochemical strategy that enables divergent synthesis of valuable C7chlorinated and alkylated (arylated) quinolines from simple ortho-propynolaniline precursors. This method leverages electrooxidative dearomatization to generate key cyclohexadienimine intermediates, which undergo two distinct pathways dictated by the para-substituent: TMSCl-mediated cascade chlorination/cyclization delivers 4,7-dichloroquinolines, while substrates bearing para-alkyl/aryl groups (R 2 ≠ Me) undergo an aromatization-driven [1,2]-σ migration to furnish 4-chloro-7-alkyl/arylquinolines with high selectivity. This approach bypasses the reliance on pre-functionalized meta-chloroanilines substrates and hazardous chlorinating agents, operating under mild conditions. Gram-scale synthesis and further derivatizations highlight the practical utility of this method, offering a versatile and sustainable platform for constructing complex quinoline architectures.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"30 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134069","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}
Fluorine-containing organic molecules have been widely utilized in the fields of medicinal chemistry, synthetic chemistry, agrochemistry and materials science, due to their higher lipophilicity, metabolic stability, cell membrane permeability, bioactivity, and other advantageous properties. Among these, gem-difluoroalkenes have emerged as privileged carbonyl bioisosteres in drug design, exemplified by antimalarial difluoroartemisinin derivatives. Recent breakthroughs in visible-light photocatalysis have enabled mild, radical-mediated allylic defluorination of these substrates through single-electron transfer (SET) processes followed by β-fluorine elimination. This review highlights cutting-edge photochemical strategies (2022-2025) for constructing gem-difluoroalkenes, emphasizing mechanistic insights and functional group compatibility. The development of these sustainable methods addresses critical challenges in fluoroorganic synthesis while expanding accessible molecular diversity for medicinal applications.
{"title":"Recent Advances in Visible-Light-Induced Defluorinative Functionalization of α-Trifluoromethyl Arylalkenes","authors":"Yanyan He, Leiyang Lv, Zhenhua Jia, Teck Peng Loh","doi":"10.1039/d5qo01732g","DOIUrl":"https://doi.org/10.1039/d5qo01732g","url":null,"abstract":"Fluorine-containing organic molecules have been widely utilized in the fields of medicinal chemistry, synthetic chemistry, agrochemistry and materials science, due to their higher lipophilicity, metabolic stability, cell membrane permeability, bioactivity, and other advantageous properties. Among these, gem-difluoroalkenes have emerged as privileged carbonyl bioisosteres in drug design, exemplified by antimalarial difluoroartemisinin derivatives. Recent breakthroughs in visible-light photocatalysis have enabled mild, radical-mediated allylic defluorination of these substrates through single-electron transfer (SET) processes followed by β-fluorine elimination. This review highlights cutting-edge photochemical strategies (2022-2025) for constructing gem-difluoroalkenes, emphasizing mechanistic insights and functional group compatibility. The development of these sustainable methods addresses critical challenges in fluoroorganic synthesis while expanding accessible molecular diversity for medicinal applications.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"28 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122485","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}
We report an aerobic three-component reaction of isatoic anhydrides, anilines, and acrylamides that simultaneously forms two distinct C–N bonds through two sequential Pd(II)-catalyzed cycles, affording 2,3-dihydroquinazolin-4(1H)-ones (DHQs) incorporating β-amino carbonyl motifs. The presence of O2 is essential for chemoselective formation of DHQs; in its absence, the reaction instead affords the competing aza-Michael adduct. To understand the origin of this chemoselectivity, we investigated the mechanistic details of the reaction using DFT calculations. Our results reveal that, in the pathway leading to DHQs, the first C–N bond is formed through a Pd(II)-catalyzed oxidative C–H/N–H coupling, for which O2 is indispensable. O2 reacts with a Pd–H intermediate formed in the cycle, generating a Pd–hydroperoxide species that promotes catalyst turnover via H2O2 release. The second C–N bond is then formed through an intramolecular nucleophilic addition, furnishing the cyclic DHQ scaffold.
{"title":"Pd(II)-Catalyzed Aerobic Dual C–N Bond Formation: Oxygen-Dependent Divergence between Dihydroquinazolinone and Aza-Michael Pathways, an Experimental and Computational Study","authors":"Narges Mohammadi, Farnaz Jafarpour, Leyla Mohammadkhani, Alireza Ariafard","doi":"10.1039/d5qo01381j","DOIUrl":"https://doi.org/10.1039/d5qo01381j","url":null,"abstract":"We report an aerobic three-component reaction of isatoic anhydrides, anilines, and acrylamides that simultaneously forms two distinct C–N bonds through two sequential Pd(II)-catalyzed cycles, affording 2,3-dihydroquinazolin-4(1H)-ones (DHQs) incorporating β-amino carbonyl motifs. The presence of O2 is essential for chemoselective formation of DHQs; in its absence, the reaction instead affords the competing aza-Michael adduct. To understand the origin of this chemoselectivity, we investigated the mechanistic details of the reaction using DFT calculations. Our results reveal that, in the pathway leading to DHQs, the first C–N bond is formed through a Pd(II)-catalyzed oxidative C–H/N–H coupling, for which O2 is indispensable. O2 reacts with a Pd–H intermediate formed in the cycle, generating a Pd–hydroperoxide species that promotes catalyst turnover via H2O2 release. The second C–N bond is then formed through an intramolecular nucleophilic addition, furnishing the cyclic DHQ scaffold.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"133 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146139049","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}
Deuterium-labelling technology has emerged as a new promising direction for the pharmaceutical discovery. Developing a divergent protocol to incorporating deuterium into different sites of bioactive molecules is highly desirable, as it opens a diverse access for leading compounds. Herein, we developed a site-selectivity divergent protocol for the deuteration of allylic esters via an electrochemical reduction approach. In the transformation, the reaction solvents and cathodes jointly dictated the reaction mechanism and active intermediates, and led to D3-incorporation and mono-deuteration products.The synthetic utility of the electrochemical protocol is highlighted in the synthesis of D-labelling ACP synthase inhibitors.Further mechanistic studies involving linear sweep voltammetry (LSV) and gas chromatography (GC) confirmed that the observed selectivity originates from distinct reaction pathways.
{"title":"Electrochemical Deuteration of Allylic Esters with Divergent Site-Selectivity","authors":"Xu Zhang, Ke Liu, Mohan Wang, Chao Wu, Xiaoli Wang, Man-Bo Li, Sheng Zhang","doi":"10.1039/d5qo01759a","DOIUrl":"https://doi.org/10.1039/d5qo01759a","url":null,"abstract":"Deuterium-labelling technology has emerged as a new promising direction for the pharmaceutical discovery. Developing a divergent protocol to incorporating deuterium into different sites of bioactive molecules is highly desirable, as it opens a diverse access for leading compounds. Herein, we developed a site-selectivity divergent protocol for the deuteration of allylic esters via an electrochemical reduction approach. In the transformation, the reaction solvents and cathodes jointly dictated the reaction mechanism and active intermediates, and led to D3-incorporation and mono-deuteration products.The synthetic utility of the electrochemical protocol is highlighted in the synthesis of D-labelling ACP synthase inhibitors.Further mechanistic studies involving linear sweep voltammetry (LSV) and gas chromatography (GC) confirmed that the observed selectivity originates from distinct reaction pathways.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"91 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146134072","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}
Mengyao Zhang, Chongjie Su, Hongguang Du, Jiaxi Xu
Blue light promoted reaction of phosphoryl diazomethanes and N-acylimines accesses 3,4-dihydro-1,5,2-oxazaphosphinine 2oxides in satisfactory to excellent yields with excellent diastereoselectivities. The reaction is a tandem sequence of the light-induced Wolff rearrangement of phosphoryl diazomethanes to phosphenes and a subsequent concerted [2 + 4] heteroatom-Diels-Alder cycloaddition of phosphenes and N-acylimines, affording highly diastereoselective trans-3,4-dihydro-1,5,2oxazaphosphinine 2-oxides. The reaction features readily available starting materials, high atom-economy, no catalyst, high diastereoselectivity, and mild conditions.
{"title":"Blue light-promoted [2 + 4] cycloaddition of phosphe-nes and N-acylimines: Highly diastereoselective access to 3,4-dihydro-1,5,2-oxazaphosphinine 2-oxides","authors":"Mengyao Zhang, Chongjie Su, Hongguang Du, Jiaxi Xu","doi":"10.1039/d6qo00019c","DOIUrl":"https://doi.org/10.1039/d6qo00019c","url":null,"abstract":"Blue light promoted reaction of phosphoryl diazomethanes and N-acylimines accesses 3,4-dihydro-1,5,2-oxazaphosphinine 2oxides in satisfactory to excellent yields with excellent diastereoselectivities. The reaction is a tandem sequence of the light-induced Wolff rearrangement of phosphoryl diazomethanes to phosphenes and a subsequent concerted [2 + 4] heteroatom-Diels-Alder cycloaddition of phosphenes and N-acylimines, affording highly diastereoselective trans-3,4-dihydro-1,5,2oxazaphosphinine 2-oxides. The reaction features readily available starting materials, high atom-economy, no catalyst, high diastereoselectivity, and mild conditions.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"3 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122311","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}
A general process for synthesizing α-sulfenylated carbonyl compounds has been developed, involving a two-step procedure. This protocol employs gold-catalyzed rearrangement of propargylic sulfoxides followed by visible-light-induced nickel-catalyzed Giese reaction of the resulting α-thioenones and DHPs or α-silylamines to afford keto thioethers in moderate to good yields. Furthermore, this transformation exhibits compatibility with diverse functional groups. α-Sulfenylated carbonyl products are versatile intermediates, suitable for late-stage structural modification.
{"title":"Synthesis of α-sulfenylated carbonyl compounds via combining gold-catalyzed rearrangement and photoinduced nickel-catalyzed Giese reaction","authors":"Yue-Liu-Ting Fu, Yun-Long Han, Liang-Qiu Lu, Ying Cheng, Wen-Jing Xiao","doi":"10.1039/d5qo01721a","DOIUrl":"https://doi.org/10.1039/d5qo01721a","url":null,"abstract":"A general process for synthesizing α-sulfenylated carbonyl compounds has been developed, involving a two-step procedure. This protocol employs gold-catalyzed rearrangement of propargylic sulfoxides followed by visible-light-induced nickel-catalyzed Giese reaction of the resulting α-thioenones and DHPs or α-silylamines to afford keto thioethers in moderate to good yields. Furthermore, this transformation exhibits compatibility with diverse functional groups. α-Sulfenylated carbonyl products are versatile intermediates, suitable for late-stage structural modification.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"9 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146122486","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}
Efficient Diels-Alder dimerizations of ene-allenes and enyne-allenes to generate highly functionalized spirocycles and the DFT studies of their exo/endo mode and stereoselectivity are described. The ene-allenes and enyne-allenes are generated in situ via the propargylic Alder-ene reaction of alkyne ene-donors tethered to ene-acceptor alkynes or 1,3-diynes. The chemo-, regio-, and stereoselectivities of the dimerization depend on the tether structure and the substituents on the ene-donors and acceptors, while the solvent plays a crucial role in the [1,5]-H shift of the dimers.
{"title":"Diels-Alder Dimerization of Ene-Allenes and Enyne-Allenes Generated via the Propargylic Alder-Ene Reaction of Diynes and Triynes","authors":"Kumudi Jayanada Weerasinghe Rajapaksa, Duy-Viet Vo, Wu Tong Tong, Yanshu Luo, Eunhye Lee, Yuanzhi Xia, Daesung Lee","doi":"10.1039/d5qo01454a","DOIUrl":"https://doi.org/10.1039/d5qo01454a","url":null,"abstract":"Efficient Diels-Alder dimerizations of ene-allenes and enyne-allenes to generate highly functionalized spirocycles and the DFT studies of their exo/endo mode and stereoselectivity are described. The ene-allenes and enyne-allenes are generated in situ via the propargylic Alder-ene reaction of alkyne ene-donors tethered to ene-acceptor alkynes or 1,3-diynes. The chemo-, regio-, and stereoselectivities of the dimerization depend on the tether structure and the substituents on the ene-donors and acceptors, while the solvent plays a crucial role in the [1,5]-H shift of the dimers.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"33 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115607","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}
Pengkuo Shi, Chun Yang, Nana Shen, Haiyun Xu, Xinying Zhang, Xuesen Fan
Presented herein is a concise and divergent synthesis of oxindole spirohydropyridine derivatives based on the reaction of enaminone with diazo oxindole. In forming the hydropyridine skeleton, one enaminone acts as a C2N1 synthon and another enaminone acts as a C2 synthon while diazo oxindole acts as a C1 synthon. Interestingly, by altering the substructure of enaminone, spirotetrahydropyridine or spirodihydropyridine scaffold could be constructed in a highly selective manner. To our knowledge, this should be the first report on the synthesis of diversely substituted oxindole spirohydropyridine derivatives based on alkenyl C−H bond activation-initiated cascade reaction of enaminone with diazo compound. In general, this novel protocol features simple and affordable substrates, valuable products, concise one-pot procedure, intriguing reaction pathway, excellent selectivity, good step-/atom-economy, and ready scalability.
{"title":"CHA-Initiated [3 + 2 + 1] Spiroannulation of Enaminone with Diazo Oxindole Leading to Concise and Divergent Synthesis of Oxindole Spirohydropyridines","authors":"Pengkuo Shi, Chun Yang, Nana Shen, Haiyun Xu, Xinying Zhang, Xuesen Fan","doi":"10.1039/d5qo01702e","DOIUrl":"https://doi.org/10.1039/d5qo01702e","url":null,"abstract":"Presented herein is a concise and divergent synthesis of oxindole spirohydropyridine derivatives based on the reaction of enaminone with diazo oxindole. In forming the hydropyridine skeleton, one enaminone acts as a C2N1 synthon and another enaminone acts as a C2 synthon while diazo oxindole acts as a C1 synthon. Interestingly, by altering the substructure of enaminone, spirotetrahydropyridine or spirodihydropyridine scaffold could be constructed in a highly selective manner. To our knowledge, this should be the first report on the synthesis of diversely substituted oxindole spirohydropyridine derivatives based on alkenyl C−H bond activation-initiated cascade reaction of enaminone with diazo compound. In general, this novel protocol features simple and affordable substrates, valuable products, concise one-pot procedure, intriguing reaction pathway, excellent selectivity, good step-/atom-economy, and ready scalability.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"64 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115609","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}
Alejandro Lumbreras-Teijeiro, Daniel Pérez de los Cobos-Pérez, Susi Hervàs-Arnandis, Marta Mon, Judit Oliver-Meseguer, Antonio Leyva-Perez
We show here that the ester-assisted hydration of alkynyl β-ketoesters does not require any commercial metal catalyst but just protons in water (either in solution or on a recyclable solid) or metals recycled from e-waste (typically Au) to give not the expected ketones but a variety of polymethylated carbocycle compounds (hydroindanes, decalines, cyclohexanones and fluorenes) in good yields and selectivity, after a three-to-five step cascade reaction.
{"title":"A metal-free or metal e-waste catalysed alkyne hydrationcondensation-decarboxylation cascade reaction in water gives access to (fused) carbocycles","authors":"Alejandro Lumbreras-Teijeiro, Daniel Pérez de los Cobos-Pérez, Susi Hervàs-Arnandis, Marta Mon, Judit Oliver-Meseguer, Antonio Leyva-Perez","doi":"10.1039/d5qo01729g","DOIUrl":"https://doi.org/10.1039/d5qo01729g","url":null,"abstract":"We show here that the ester-assisted hydration of alkynyl β-ketoesters does not require any commercial metal catalyst but just protons in water (either in solution or on a recyclable solid) or metals recycled from e-waste (typically Au) to give not the expected ketones but a variety of polymethylated carbocycle compounds (hydroindanes, decalines, cyclohexanones and fluorenes) in good yields and selectivity, after a three-to-five step cascade reaction.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"108 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146101953","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}
Herein, we report a Pd-catalyzed, base-controlled divergent cyclization strategy for the synthesis of polycyclic indole derivatives. Utilizing 3-propargyl indoles and ortho-iodophenyl-ynones as substrates, the reaction pathway can be tuned by the choice of a base: (1) with DIPA, the reaction proceeds through Pd-catalyzed cross-coupling, propargylic Alder ene-type reaction (1,8-H transfer), and indole-migrative cyclization to afford cycloheptatriene[b]indole scaffolds; (2) NIS was incorporated into the reaction system with the purpose of capturing the indole-allene intermediate, and it successfully yielded spiro cyclopentene[b]indole derivatives; (3) alternatively, DBU promotes a distinct pathway involving Pd-catalyzed cross-coupling, propargyl-allenyl isomerization (1,3-H transfer), [4+2] cycloaddition and aromatization to generate carbazole scaffolds. The proposed reaction mechanism is supported by experimental investigations.
{"title":"Skeletal diversity-oriented synthesis of cycloheptatriene[b]indole, spiro-cyclopentene[b]indole and carbazole derivatives via Pd-catalyzed sequential reaction involving indolyl allene intermediates","authors":"Yu Xin, Xinxin Chen, Zebang Meng, Ruwei Shen, Shugao Zhu","doi":"10.1039/d5qo01651g","DOIUrl":"https://doi.org/10.1039/d5qo01651g","url":null,"abstract":"Herein, we report a Pd-catalyzed, base-controlled divergent cyclization strategy for the synthesis of polycyclic indole derivatives. Utilizing 3-propargyl indoles and ortho-iodophenyl-ynones as substrates, the reaction pathway can be tuned by the choice of a base: (1) with DIPA, the reaction proceeds through Pd-catalyzed cross-coupling, propargylic Alder ene-type reaction (1,8-<em>H</em> transfer), and indole-migrative cyclization to afford cycloheptatriene[<em>b</em>]indole scaffolds; (2) NIS was incorporated into the reaction system with the purpose of capturing the indole-allene intermediate, and it successfully yielded spiro cyclopentene[<em>b</em>]indole derivatives; (3) alternatively, DBU promotes a distinct pathway involving Pd-catalyzed cross-coupling, propargyl-allenyl isomerization (1,3-<em>H</em> transfer), [4+2] cycloaddition and aromatization to generate carbazole scaffolds. The proposed reaction mechanism is supported by experimental investigations.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"6 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2026-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146115610","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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