Chalcogen bonding has emeged as a new catalysis strategy capable of solving reactivity and selectivity problems in a diverse array of chemical reactions. Yet, a macrocyclic chalcogen bonding catalysis system remains undeveloped in this field. Here, we report the first example on the development of macrocyclic chalcogen bonding catalysts and the proof-of-concept studies on their catalysis capability. The tellurium centers in these macrocyclic chalcogen bonding catalysts can form competitive host-guest interactions between catalyst and glycosyl acceptors and donors, enabling the development of a dynamic glycosylation approach. In the presence of the same macrocyclic catalyst and the same reactants, the glycosylation process could be controlled to shift between SN1 and SN2 reaction pathways through the formation of different host-guest complexes. This dynamic glycosylation mechanism can lead to high stereoselectivity through simply increasing the concentration of glycosyl acceptors.
{"title":"A Macrocyclic Chalcogen Bonding Catalysis System","authors":"Wei Wang, Baojie Yu, Yu-Cheng Gu, Yao Wang","doi":"10.1039/d5qo00101c","DOIUrl":"https://doi.org/10.1039/d5qo00101c","url":null,"abstract":"Chalcogen bonding has emeged as a new catalysis strategy capable of solving reactivity and selectivity problems in a diverse array of chemical reactions. Yet, a macrocyclic chalcogen bonding catalysis system remains undeveloped in this field. Here, we report the first example on the development of macrocyclic chalcogen bonding catalysts and the proof-of-concept studies on their catalysis capability. The tellurium centers in these macrocyclic chalcogen bonding catalysts can form competitive host-guest interactions between catalyst and glycosyl acceptors and donors, enabling the development of a dynamic glycosylation approach. In the presence of the same macrocyclic catalyst and the same reactants, the glycosylation process could be controlled to shift between S<small><sub>N</sub></small>1 and S<small><sub>N</sub></small>2 reaction pathways through the formation of different host-guest complexes. This dynamic glycosylation mechanism can lead to high stereoselectivity through simply increasing the concentration of glycosyl acceptors.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"85 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496080","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}
Dearomative photocycloadditions are unique and hard to replace methods for the construction of various polycyclic strained molecules to increase saturation and create three-dimensional (3D) molecular complexity. In this article, we report a facile photochemical strategy for the synthesis of pyridine-fused 3D polycyclic molecules from quinolines and bicyclo[1.1.0]butanes (BCBs) under visible-light conditions. The dearomative reactions proceed via an initial triplet–triplet energy transfer (EnT) enabled [2π + 2σ] cycloaddition to form an adduct, in which the vinylpyridine moiety is still excitable under the same photosensitive conditions. By introducing a suitable alkyl group as an H-donor into a BCB, a 1,6-hydrogen atom transfer (HAT) would occur from the alkyl group to the excited vinylpyridine moiety via a second EnT process, generating a 1,7-diradical; subsequent ring closure produces a seven-membered 2D/3D-fused molecule. The rare 1,6-HAT process was confirmed through dynamic tracking, control experiments, quenching studies and deuterium-labeling experiments. Applying this strategy, we have successfully obtained a series of structurally unique 6-6-5-4-7 ring 3D molecules with wide functional group tolerance and compatibility with various C–H bonds and various quinolines. Meanwhile, it provides a new idea for the construction of polycyclic architectures by utilizing the infrequent 1,6-HAT of an excited olefin to generate 1,7-diradical species.
{"title":"Successive energy-transfer catalytic dearomative reactions of quinolines with bicyclo[1.1.0]butanes for the synthesis of pyridine-fused 3D complicated molecules","authors":"Yi-Ping Cai, Shi-Ru Chen, Qin-Hua Song","doi":"10.1039/d5qo00205b","DOIUrl":"https://doi.org/10.1039/d5qo00205b","url":null,"abstract":"Dearomative photocycloadditions are unique and hard to replace methods for the construction of various polycyclic strained molecules to increase saturation and create three-dimensional (3D) molecular complexity. In this article, we report a facile photochemical strategy for the synthesis of pyridine-fused 3D polycyclic molecules from quinolines and bicyclo[1.1.0]butanes (BCBs) under visible-light conditions. The dearomative reactions proceed <em>via</em> an initial triplet–triplet energy transfer (EnT) enabled [2π + 2σ] cycloaddition to form an adduct, in which the vinylpyridine moiety is still excitable under the same photosensitive conditions. By introducing a suitable alkyl group as an H-donor into a BCB, a 1,6-hydrogen atom transfer (HAT) would occur from the alkyl group to the excited vinylpyridine moiety <em>via</em> a second EnT process, generating a 1,7-diradical; subsequent ring closure produces a seven-membered 2D/3D-fused molecule. The rare 1,6-HAT process was confirmed through dynamic tracking, control experiments, quenching studies and deuterium-labeling experiments. Applying this strategy, we have successfully obtained a series of structurally unique 6-6-5-4-7 ring 3D molecules with wide functional group tolerance and compatibility with various C–H bonds and various quinolines. Meanwhile, it provides a new idea for the construction of polycyclic architectures by utilizing the infrequent 1,6-HAT of an excited olefin to generate 1,7-diradical species.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"6 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496178","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 novel silver-catalyzed tandem cyclization reaction of electron-deficient terminal alkynes with two molecules of sulfur ylides has been developed. The reaction provides a simple and highly efficient strategy for the synthesis of diversely functionalized vinylcyclopropanes from easily available acyclic starting materials with good to high diastereoselectivities in a single step. Mechanistic studies indicate a sequential reaction mechanism that involves methyl migration, nucleophilic addition, cyclization, electrocyclic ring-opening, and cyclopropanation. Further applications, including synthesis of vinylcyclopropanes bearing dihydroxyl groups, 3-oxabicyclo[3.1.0]hexanes and biphenyls, demonstrated the immense potential of the tandem cyclization.
{"title":"Silver-Catalyzed Tandem Cyclization of Sulfur Ylides with Terminal Alkynes: Direct Synthesis of Vinylcyclopropanes","authors":"Yue Gong, Xue-Cen Xu, Yu-Xuan Meng, Yu-Long Zhao","doi":"10.1039/d5qo00012b","DOIUrl":"https://doi.org/10.1039/d5qo00012b","url":null,"abstract":"A novel silver-catalyzed tandem cyclization reaction of electron-deficient terminal alkynes with two molecules of sulfur ylides has been developed. The reaction provides a simple and highly efficient strategy for the synthesis of diversely functionalized vinylcyclopropanes from easily available acyclic starting materials with good to high diastereoselectivities in a single step. Mechanistic studies indicate a sequential reaction mechanism that involves methyl migration, nucleophilic addition, cyclization, electrocyclic ring-opening, and cyclopropanation. Further applications, including synthesis of vinylcyclopropanes bearing dihydroxyl groups, 3-oxabicyclo[3.1.0]hexanes and biphenyls, demonstrated the immense potential of the tandem cyclization.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"51 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496079","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}
Correction for ‘AI molecular catalysis: where are we now?’ by Zhenzhi Tan et al., Org. Chem. Front., 2025, https://doi.org/10.1039/d4qo02363c.
{"title":"Correction: AI molecular catalysis: where are we now?","authors":"Zhenzhi Tan, Qi Yang, Sanzhong Luo","doi":"10.1039/d5qo90021b","DOIUrl":"https://doi.org/10.1039/d5qo90021b","url":null,"abstract":"Correction for ‘AI molecular catalysis: where are we now?’ by Zhenzhi Tan <em>et al.</em>, <em>Org. Chem. Front.</em>, 2025, https://doi.org/10.1039/d4qo02363c.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"66 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143496078","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}
An efficient iridium-catalyzed asymmetric hydrogenation (AH) of tetrahydro-γ-carboline has been developed for the synthesis of chiral cis-hexahydro-γ-carboline derivatives. This method overcomes the challenge posed by C6 substituents on the carboline ring, proceeding smoothly under mild conditions to deliver the desired products in high yields with exceptional enantioselectivities. The success of this transformation is attributed to the use of a ZhaoPhos ligand bearing an electron-withdrawing F-substituted phenyl group on phosphorus. Notably, the strategy's versatility is further demonstrated by its concise and efficient application in the synthesis of lumateperone intermediates.
{"title":"Iridium-Catalyzed Asymmetric Hydrogenation of Tetrahydro-γ-Carboline: A Versatile Approach to Chiral cis-Hexahydro-γ-Carboline Derivatives Compatible with C6-Substituted Carbolines","authors":"Xumu Zhang, Xiuxiu Li, Chun Zhang, Bowen Liu","doi":"10.1039/d4qo02448f","DOIUrl":"https://doi.org/10.1039/d4qo02448f","url":null,"abstract":"An efficient iridium-catalyzed asymmetric hydrogenation (AH) of tetrahydro-γ-carboline has been developed for the synthesis of chiral cis-hexahydro-γ-carboline derivatives. This method overcomes the challenge posed by C6 substituents on the carboline ring, proceeding smoothly under mild conditions to deliver the desired products in high yields with exceptional enantioselectivities. The success of this transformation is attributed to the use of a ZhaoPhos ligand bearing an electron-withdrawing F-substituted phenyl group on phosphorus. Notably, the strategy's versatility is further demonstrated by its concise and efficient application in the synthesis of lumateperone intermediates.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"66 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486510","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}
An electrochemical dehydrogenative annulation under mild conditions has been developed, which offers a simple and efficient way to access synthetically useful isoxazolines and pyrazolines. This methodology demonstrates remarkable scalability, as evidenced by successful gram-scale synthesis through both continuous-flow and batch electrolysis. The synthetic utility of this protocol was further highlighted by the efficient preparation of Parecoxib, a clinically important COX-2 inhibitor, on a gram scale from commercially available starting materials. Furthermore, we have also successfully extended this electrochemical strategy to achieve the desulfurative annulation of thioethers.
{"title":"Electrochemical Dehydrogenative and Desulfurative Annulation for the Synthesis of Isoxazolines and Pyrazolines","authors":"Qiang Wang, Xing Zhang, Xianglin Zhuang, Liwen Xia, Ying-Wei Wang, Xianrong Cai, Xing-Yong Liang, Lebin Su","doi":"10.1039/d5qo00135h","DOIUrl":"https://doi.org/10.1039/d5qo00135h","url":null,"abstract":"An electrochemical dehydrogenative annulation under mild conditions has been developed, which offers a simple and efficient way to access synthetically useful isoxazolines and pyrazolines. This methodology demonstrates remarkable scalability, as evidenced by successful gram-scale synthesis through both continuous-flow and batch electrolysis. The synthetic utility of this protocol was further highlighted by the efficient preparation of Parecoxib, a clinically important COX-2 inhibitor, on a gram scale from commercially available starting materials. Furthermore, we have also successfully extended this electrochemical strategy to achieve the desulfurative annulation of thioethers.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"26 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486507","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}
Ruisheng Zhao, Chaomin Hao, Dan Liu, Zizhong Liu, Yong-Sheng Bao
A general practical type of Cu/DMAP cocatalyzed and DMAP-catalyzed C-N decarboxylative cross-coupling (DCC) reactions of carboxylic acids (or carboxylates) and azdioformates, which can construct both C(sp2)-N and C(sp3)-N bonds, was thoroughly investigated by density functional theory calculations. The Curtius Rearrangements, i.e. extrusions of N2, were exposed to be the rate-limiting steps for both Cu/MDAP cocatalyzed and DMAP-catalyzed C-N DCC reactions. DMAP can facilitate the N3- transfer from the initial azidoformate species to the ensuing generated acyl azide intermediates. Then, the acyl azide intermediates undergo the Curtius Rearrangements, overcoming a relatively low barrier. If DMAP were absent, the Curtius Rearrangements would have to occur on the initial azidoformate species with barriers over 40.0 kcal/mol, which is not feasible at room temperature. Cu catalysts can further slightly facilitate the C-N DCC reactions.
{"title":"Mechanisms of Cu/DMAP Cocatalyzed and DMAP-Catalyzed C-N Decarboxylative Cross-Coupling Reactions","authors":"Ruisheng Zhao, Chaomin Hao, Dan Liu, Zizhong Liu, Yong-Sheng Bao","doi":"10.1039/d4qo02352h","DOIUrl":"https://doi.org/10.1039/d4qo02352h","url":null,"abstract":"A general practical type of Cu/DMAP cocatalyzed and DMAP-catalyzed C-N decarboxylative cross-coupling (DCC) reactions of carboxylic acids (or carboxylates) and azdioformates, which can construct both C(sp2)-N and C(sp3)-N bonds, was thoroughly investigated by density functional theory calculations. The Curtius Rearrangements, i.e. extrusions of N2, were exposed to be the rate-limiting steps for both Cu/MDAP cocatalyzed and DMAP-catalyzed C-N DCC reactions. DMAP can facilitate the N3- transfer from the initial azidoformate species to the ensuing generated acyl azide intermediates. Then, the acyl azide intermediates undergo the Curtius Rearrangements, overcoming a relatively low barrier. If DMAP were absent, the Curtius Rearrangements would have to occur on the initial azidoformate species with barriers over 40.0 kcal/mol, which is not feasible at room temperature. Cu catalysts can further slightly facilitate the C-N DCC reactions.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"15 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486511","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}
Qing He, Yu-Qi Xiang, Rui Zhou, Bin Liu, Rong-Hua Wang, Xiang-Kai Kong, Song Bai, Miao Li, Guang-Jun Yang, Gao-Feng Zhu
A low catalyst loading and transition metal-free benzannulation of β,γ-alkynyl-α-keto esters and CF3-alkenes has been developed through Michael-triggered [3 + 3] annulation. The newly developed methodology provides highly efficient and rapid access to a variety of multi-functionalised trifluoromethylarene derivatives in generally good to excellent yields. The late-stage functionalisation of some natural products and bioactive molecules and the gram-scale reaction as well as transformation of the products indicate that the present protocol has significant practical value and reliability.
{"title":"Metal-free catalytic de novo construction of multi-functionalized trifluoromethylarenes through [3 + 3] benzannulation at low catalyst loadings","authors":"Qing He, Yu-Qi Xiang, Rui Zhou, Bin Liu, Rong-Hua Wang, Xiang-Kai Kong, Song Bai, Miao Li, Guang-Jun Yang, Gao-Feng Zhu","doi":"10.1039/d5qo00013k","DOIUrl":"https://doi.org/10.1039/d5qo00013k","url":null,"abstract":"A low catalyst loading and transition metal-free benzannulation of β,γ-alkynyl-α-keto esters and CF<small><sub>3</sub></small>-alkenes has been developed through Michael-triggered [3 + 3] annulation. The newly developed methodology provides highly efficient and rapid access to a variety of multi-functionalised trifluoromethylarene derivatives in generally good to excellent yields. The late-stage functionalisation of some natural products and bioactive molecules and the gram-scale reaction as well as transformation of the products indicate that the present protocol has significant practical value and reliability.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"26 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486506","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}
Jia-Lin Tu, Ao-Men Hu, Chao Yang, Lin Guo, Wujiong Xia
Electrocatalysis and photocatalysis have both emerged as increasingly feasible platforms in sustainable synthesis. This study explores a novel photoelectrochemical synergistic strategy, achieving non-directed C(sp3)–H alkenylation reaction utilizing an iron-cobalt dual catalytic system. With the synergy of photoelectrochemical redox catalysis and iron-cobalt catalysis, efficient C(sp3)–H alkenylation reaction of alkanes as well as dehydrogenation occur without the need for external oxidants, yielding hydrogen gas as the sole byproduct. This method demonstrates unconventional regioselectivity, with a preference for alkenylation at the 1° C–H bonds. This research not only demonstrates that alkenes as radical acceptors can influence the regioselectivity but also offers a promising pathway for advancing iron-catalyzed C–H functionalization.
{"title":"Photoelectrochemical Iron-Cobalt Synergistic Catalysis for C(sp3)–H Alkenylation","authors":"Jia-Lin Tu, Ao-Men Hu, Chao Yang, Lin Guo, Wujiong Xia","doi":"10.1039/d5qo00017c","DOIUrl":"https://doi.org/10.1039/d5qo00017c","url":null,"abstract":"Electrocatalysis and photocatalysis have both emerged as increasingly feasible platforms in sustainable synthesis. This study explores a novel photoelectrochemical synergistic strategy, achieving non-directed C(sp3)–H alkenylation reaction utilizing an iron-cobalt dual catalytic system. With the synergy of photoelectrochemical redox catalysis and iron-cobalt catalysis, efficient C(sp3)–H alkenylation reaction of alkanes as well as dehydrogenation occur without the need for external oxidants, yielding hydrogen gas as the sole byproduct. This method demonstrates unconventional regioselectivity, with a preference for alkenylation at the 1° C–H bonds. This research not only demonstrates that alkenes as radical acceptors can influence the regioselectivity but also offers a promising pathway for advancing iron-catalyzed C–H functionalization.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"22 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486508","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}
The selective activation and functionalization of C-F bonds remain significant challenges in synthetic and medicinal chemistry. Herein, we report a solvent-promoted strategy for selective C-F bond activation, enabling the hydrodefluorination and hydroxydefluorination of indole using heptafluoro-2-iodopropane in the presence of sodium dithionite (Na₂S₂O₄). This method offers efficient access to a wide range of fluorinated indole derivatives under mild reaction conditions, achieving good yields.
{"title":"Selective perfluoroalkylation and defluorination functionalization of Indoles","authors":"Meina Li, Guizhao Wang, Faqiang LENG","doi":"10.1039/d5qo00024f","DOIUrl":"https://doi.org/10.1039/d5qo00024f","url":null,"abstract":"The selective activation and functionalization of C-F bonds remain significant challenges in synthetic and medicinal chemistry. Herein, we report a solvent-promoted strategy for selective C-F bond activation, enabling the hydrodefluorination and hydroxydefluorination of indole using heptafluoro-2-iodopropane in the presence of sodium dithionite (Na₂S₂O₄). This method offers efficient access to a wide range of fluorinated indole derivatives under mild reaction conditions, achieving good yields.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":"32 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143486514","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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