Part belt oxygen-functionalized pillar[6,10]arenes are synthesized by step cyclization. An oxygen-substituted tetramer and hexamer have been prepared to construct the O3 pillar[6]arene 4 via a hexamer cyclization reaction and the O6 pillar[10]arene 7 through a [4 + 1+4 + 1] cyclization reaction. X-ray crystallographic studies reveal that both macrocycles have a large cavity and indicate that the part belt oxygen-functionalized pillar[6,10]arenes have both similar cyclic structures and certain differences in configuration compared to pillararene. A variable-temperature 1H NMR experiment also demonstrated the structure differences between O3 pillar[6]arene 4 and traditional pillararene.
{"title":"Step Cyclization to Give Part Belt Oxygen-Functionalized Pillar[6,10]arenes","authors":"Weijian Xue, Yuhang Liu, Huiqian Li, Xiangyu Ling, Bing Zhao, Yanbing Yin","doi":"10.1021/acs.orglett.4c04607","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04607","url":null,"abstract":"Part belt oxygen-functionalized pillar[6,10]arenes are synthesized by step cyclization. An oxygen-substituted tetramer and hexamer have been prepared to construct the O3 pillar[6]arene <b>4</b> via a hexamer cyclization reaction and the O6 pillar[10]arene <b>7</b> through a [4 + 1+4 + 1] cyclization reaction. X-ray crystallographic studies reveal that both macrocycles have a large cavity and indicate that the part belt oxygen-functionalized pillar[6,10]arenes have both similar cyclic structures and certain differences in configuration compared to pillararene. A variable-temperature <sup>1</sup>H NMR experiment also demonstrated the structure differences between O3 pillar[6]arene <b>4</b> and traditional pillararene.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"166 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142902119","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}
Pub Date : 2024-12-29DOI: 10.1021/acs.orglett.4c04350
Wei-Ming Liu, Yong-Jiu Hao, Yuan Zhang, Xian-Gao Li, Shun-Jun Ji, Zhong-Jian Cai
The azahelicenes are structurally fascinating and practically useful chiral scaffolds, but their synthesis, especially in a catalytically asymmetric manner, is rather challenging. Herein, we report a CPA-catalyzed transfer hydrogenation process, which enables a rapid kinetic resolution of aza[6]helicenes. The established strategy provides facile access to enantioenriched aza[6]helicenes and tetrahydro[6]helicenes from easily available starting materials. A gram-scale reaction and facile conversion of the helical products into a promising chiral Lewis base catalyst, a chiroptical switch material, and monophosphine ligands further highlight the potential application of this protocol.
{"title":"Asymmetric Synthesis of Azahelicenes via CPA-Catalyzed Kinetic Resolution","authors":"Wei-Ming Liu, Yong-Jiu Hao, Yuan Zhang, Xian-Gao Li, Shun-Jun Ji, Zhong-Jian Cai","doi":"10.1021/acs.orglett.4c04350","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04350","url":null,"abstract":"The azahelicenes are structurally fascinating and practically useful chiral scaffolds, but their synthesis, especially in a catalytically asymmetric manner, is rather challenging. Herein, we report a CPA-catalyzed transfer hydrogenation process, which enables a rapid kinetic resolution of aza[6]helicenes. The established strategy provides facile access to enantioenriched aza[6]helicenes and tetrahydro[6]helicenes from easily available starting materials. A gram-scale reaction and facile conversion of the helical products into a promising chiral Lewis base catalyst, a chiroptical switch material, and monophosphine ligands further highlight the potential application of this protocol.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"23 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142901938","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}
Pub Date : 2024-12-28DOI: 10.1021/acs.orglett.4c04373
Guanghao Ji, Xuan Li, Jing Zhang
Herein we describe a dual photo/cobalt-catalyzed anti-Markovnikov hydroacylation of aryl alkenes using aldehyde as acyl source. The key to success is the cobalt catalyzed hydrogen atom transfer, which enables effective formation of the desired products and efficient regeneration of the photocatalyst under mild conditions. This protocol features broad substrate scopes, good functional group tolerance, high efficiency and regioselectivity.
{"title":"Anti-Markovnikov Hydroacylation of Aryl Alkenes with Aldehydes Enabled by Photo/Cobalt Dual Catalysis","authors":"Guanghao Ji, Xuan Li, Jing Zhang","doi":"10.1021/acs.orglett.4c04373","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04373","url":null,"abstract":"Herein we describe a dual photo/cobalt-catalyzed anti-Markovnikov hydroacylation of aryl alkenes using aldehyde as acyl source. The key to success is the cobalt catalyzed hydrogen atom transfer, which enables effective formation of the desired products and efficient regeneration of the photocatalyst under mild conditions. This protocol features broad substrate scopes, good functional group tolerance, high efficiency and regioselectivity.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"51 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888029","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}
Pub Date : 2024-12-28DOI: 10.1021/acs.orglett.4c04342
Subhankar Biswas, Subhas Chandra Pan
Herein, an organocatalytic asymmetric desymmetrizing [4+2] cycloaddition/base-mediated oxidative aromatization reaction sequence has been developed between spirophthalide 2,5-cyclohexadienones and β-methyl cinnamaldehydes. The reaction proceeds through in situ chiral dienamine intermediate formation, and the densely functionalized spirocyclic isobenzofuranone-embedded chiral arenes were formed in high yields with excellent enantioselectivities. A 2-fold desymmetrization reaction was also performed, and the products were obtained in high enantioselectivities.
{"title":"Catalytic Asymmetric Desymmetrizing [4+2] Cycloaddition/Base-Mediated Oxidative Aromatization Sequence: De Novo Synthesis of Isobenzofuranone-Embedded Chiral Arenes","authors":"Subhankar Biswas, Subhas Chandra Pan","doi":"10.1021/acs.orglett.4c04342","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04342","url":null,"abstract":"Herein, an organocatalytic asymmetric desymmetrizing [4+2] cycloaddition/base-mediated oxidative aromatization reaction sequence has been developed between spirophthalide 2,5-cyclohexadienones and β-methyl cinnamaldehydes. The reaction proceeds through <i>in situ</i> chiral dienamine intermediate formation, and the densely functionalized spirocyclic isobenzofuranone-embedded chiral arenes were formed in high yields with excellent enantioselectivities. A 2-fold desymmetrization reaction was also performed, and the products were obtained in high enantioselectivities.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"30 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888229","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 photocatalytic alkene-migrative chain elongation reaction of 2-phosphinostyrenes with aldehydes under mild conditions in response to blue light was demonstrated. A broad range of aldehydes, both aliphatic and aromatic, participated in this reaction to afford alkene-phosphine oxides in a Z-selective manner. Mechanistic experiments suggested the formation of benzophospholene-based ylide intermediates via photocatalytic cyclization of phosphinostyrenes followed by solvent-mediated proton transfer under base-free reaction conditions.
{"title":"Photocatalytic Alkene-Migrative Chain Elongation of 2-Phosphinostyrenes with Aldehydes","authors":"Haruna Mori, Ayaka Sakurada, Masaya Sawamura, Yusuke Masuda","doi":"10.1021/acs.orglett.4c04424","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04424","url":null,"abstract":"The photocatalytic alkene-migrative chain elongation reaction of 2-phosphinostyrenes with aldehydes under mild conditions in response to blue light was demonstrated. A broad range of aldehydes, both aliphatic and aromatic, participated in this reaction to afford alkene-phosphine oxides in a <i>Z</i>-selective manner. Mechanistic experiments suggested the formation of benzophospholene-based ylide intermediates via photocatalytic cyclization of phosphinostyrenes followed by solvent-mediated proton transfer under base-free reaction conditions.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"141 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888030","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}
Pub Date : 2024-12-27DOI: 10.1021/acs.orglett.4c04454
Qun Liu, Xiaoyun Feng, Fenghao Xie, Yingchao Lai, Haokun Jiang, Yujing Jiao, Jin Wang
We herein report a photoredox N–S coupling reaction between dialkyl azodicarboxylates and thiols to access sulfenamide scaffolds. This reaction proceeds under mild, green, and operationally simple conditions, offering a broad scope of sulfenamides with high yields and excellent atom efficiency. Mechanistic investigations revealed this reaction followed a photoinitiated radical pathway in which iodide plays a crucial role as both a radical initiator and a single-electron reductant.
{"title":"Synthesis of Sulfenamides via Photoredox N–S Coupling of Dialkyl Azodicarboxylates and Thiols","authors":"Qun Liu, Xiaoyun Feng, Fenghao Xie, Yingchao Lai, Haokun Jiang, Yujing Jiao, Jin Wang","doi":"10.1021/acs.orglett.4c04454","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04454","url":null,"abstract":"We herein report a photoredox N–S coupling reaction between dialkyl azodicarboxylates and thiols to access sulfenamide scaffolds. This reaction proceeds under mild, green, and operationally simple conditions, offering a broad scope of sulfenamides with high yields and excellent atom efficiency. Mechanistic investigations revealed this reaction followed a photoinitiated radical pathway in which iodide plays a crucial role as both a radical initiator and a single-electron reductant.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"71 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888034","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 present an iron-photocatalyzed decarboxylative alkylation strategy involving carboxylic acids and Morita–Baylis–Hillman (MBH) acetates to synthesize E-type tri- and tetrasubstituted alkenes with moderate to excellent stereoselectivity (E/Z ratio up to >19:1). This method is applicable to a broad range of structurally diverse primary, secondary, and tertiary alkyl carboxylic acids, as well as complex pharmaceutical and natural carboxylic acids, achieving efficient alkylation of various MBH acetates under mild conditions (>60 examples, with yields up to 96%). This approach offers a powerful strategy for streamlined alkylation.
{"title":"Iron-Photocatalyzed Decarboxylative Alkylation of Carboxylic Acids with Morita–Baylis–Hillman Acetates","authors":"Yanli Yin, Fang Chen, Dong Chen, Peizhong Xie, Dongping Wang, Teck-Peng Loh","doi":"10.1021/acs.orglett.4c04267","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04267","url":null,"abstract":"We present an iron-photocatalyzed decarboxylative alkylation strategy involving carboxylic acids and Morita–Baylis–Hillman (MBH) acetates to synthesize <i>E</i>-type tri- and tetrasubstituted alkenes with moderate to excellent stereoselectivity (<i>E</i>/<i>Z</i> ratio up to >19:1). This method is applicable to a broad range of structurally diverse primary, secondary, and tertiary alkyl carboxylic acids, as well as complex pharmaceutical and natural carboxylic acids, achieving efficient alkylation of various MBH acetates under mild conditions (>60 examples, with yields up to 96%). This approach offers a powerful strategy for streamlined alkylation.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"1 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888232","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}
Pub Date : 2024-12-26DOI: 10.1021/acs.orglett.4c04224
Lan Zheng, Yu-Min Yang, Zhi-Ping Liu, Wei Wang, Wen-Jie Liang, Hai-Lian Jiang, Liu Yang, Chenxiang Lin, Wei Su, Jun-An Xiao
A palladium-catalyzed [2π + 2σ] cycloaddition of vinyl bicyclo[1.1.0]butanes with methyleneindolinones has been developed. The reaction enables the construction of spirobicyclo[2.1.1]hexanes bearing an all-carbon quaternary center in moderate to good yields with excellent diastereoselectivities. This method features a broad substrate scope with good functional group compatibility. The practical utility of this protocol was further demonstrated by gram-scale synthesis and postsynthetic transformations of desired product.
{"title":"Palladium-Catalyzed Strain-Enabled [2π + 2σ] Cycloadditions of Vinyl Bicyclo[1.1.0]butanes with Methyleneindolinones","authors":"Lan Zheng, Yu-Min Yang, Zhi-Ping Liu, Wei Wang, Wen-Jie Liang, Hai-Lian Jiang, Liu Yang, Chenxiang Lin, Wei Su, Jun-An Xiao","doi":"10.1021/acs.orglett.4c04224","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04224","url":null,"abstract":"A palladium-catalyzed [2π + 2σ] cycloaddition of vinyl bicyclo[1.1.0]butanes with methyleneindolinones has been developed. The reaction enables the construction of spirobicyclo[2.1.1]hexanes bearing an all-carbon quaternary center in moderate to good yields with excellent diastereoselectivities. This method features a broad substrate scope with good functional group compatibility. The practical utility of this protocol was further demonstrated by gram-scale synthesis and postsynthetic transformations of desired product.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"32 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142887216","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}
Pub Date : 2024-12-26DOI: 10.1021/acs.orglett.4c04494
Shu Wang, Ge Liang, Cheng Wang, Chen-Hong Wang, Zhiyuan Huang, Chen-Ho Tung, Li-Zhu Wu
Reported herein is the generation of ortho-quinone methides (o-QMs) via metal-free visible-light-induced oxidation of ortho-alkylarenols, as well as their subsequent reaction with olefins to afford chromans in good to excellent yields (up to 91%). The key is the selective activation of the benzylic C(sp3)–H bond of ortho-alkylarenols via single electron transfer (SET) and the formation of o-QMs via hydrogen atom transfer (HAT).
{"title":"Visible-Light-Induced ortho-Quinone Methides Formation in Situ Using ortho-Alkylarenols as Precursors for Tandem [4 + 2] Cycloaddition Reaction","authors":"Shu Wang, Ge Liang, Cheng Wang, Chen-Hong Wang, Zhiyuan Huang, Chen-Ho Tung, Li-Zhu Wu","doi":"10.1021/acs.orglett.4c04494","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04494","url":null,"abstract":"Reported herein is the generation of <i>ortho</i>-quinone methides (<i>o</i>-QMs) via metal-free visible-light-induced oxidation of <i>ortho</i>-alkylarenols, as well as their subsequent reaction with olefins to afford chromans in good to excellent yields (up to 91%). The key is the selective activation of the benzylic C(sp<sup>3</sup>)–H bond of <i>ortho</i>-alkylarenols via single electron transfer (SET) and the formation of <i>o</i>-QMs via hydrogen atom transfer (HAT).","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"1 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142887219","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}
Pub Date : 2024-12-26DOI: 10.1021/acs.orglett.4c04465
Jian-Qiang Chen, Jiapian Huang, Jiangkun Yao, Tong Wang, Yehan Feng, Xiaoyu Zhou, Min Yang, Jie Wu
In this work, we used experiments and density functional theory calculations to investigate the mechanism and driving forces of the reductive fragmentation of NHPI esters. Mechanistic studies suggest that the fragmentation behavior of the NHPI ester is influenced not only by the electronic nature of the substituent group but also by the stability of the radical intermediate. To further investigate this transformation, we next examined the aminoalkoxycarbonylation of alkenes using alkyl N-phthalimidoyl oxalates. With this approach, a variety of β-amino acid derivatives with diverse structures can be obtained in moderate to high yields.
{"title":"Photoinduced Concerted Fragmentation of Alkyl N-Phthalimidoyl Oxalates: Mechanisms and Applications","authors":"Jian-Qiang Chen, Jiapian Huang, Jiangkun Yao, Tong Wang, Yehan Feng, Xiaoyu Zhou, Min Yang, Jie Wu","doi":"10.1021/acs.orglett.4c04465","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04465","url":null,"abstract":"In this work, we used experiments and density functional theory calculations to investigate the mechanism and driving forces of the reductive fragmentation of NHPI esters. Mechanistic studies suggest that the fragmentation behavior of the NHPI ester is influenced not only by the electronic nature of the substituent group but also by the stability of the radical intermediate. To further investigate this transformation, we next examined the aminoalkoxycarbonylation of alkenes using alkyl <i>N</i>-phthalimidoyl oxalates. With this approach, a variety of β-amino acid derivatives with diverse structures can be obtained in moderate to high yields.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"23 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142888053","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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