Intramolecular chromone annulations of o-hydroxyphenylenaminones (o-HPEs) with a variety of C-H bond functionalization precursors have attracted much attention and become one of the most straightforward and efficient approaches for the rapid assembly of structurally diverse chromone compounds. However, the intermolecular chromone annulation reaction was not yet developed. Herein, we report an unprecedented metal-free-catalyzed, chemodivergent and skeleton-controllable annulation reactions of o-HPEs with aryldiazonium salts. This protocol is featured by a new intermolecular chromone annulation strategy for the divergent synthesis of pyridazin-fused chromones via adjusting the reaction temperature. Moreover, the pyridazin-fused chromones exhibits promising high antiviral activity against human coronavirus OC43 (HCoV-OC43), with higher safety compared to reference drug (Arbidol), indicating that the intermolecular chromone annulation methodology might provide assistance for drug discovery.
{"title":"Selective synthesis of pyridazin-fused chromones and 3-pyridazinyl chromones through intermolecular chromone annulation of o-hydroxyphenylenaminones with aryldiazonium salts","authors":"Siyu Song, Zhilai Zhang, Menglin Peng, Xueshan Xia, Shuwei Dong, Yong-Chao Wang, Fuchao Yu","doi":"10.1039/d4qo00677a","DOIUrl":"https://doi.org/10.1039/d4qo00677a","url":null,"abstract":"Intramolecular chromone annulations of o-hydroxyphenylenaminones (o-HPEs) with a variety of C-H bond functionalization precursors have attracted much attention and become one of the most straightforward and efficient approaches for the rapid assembly of structurally diverse chromone compounds. However, the intermolecular chromone annulation reaction was not yet developed. Herein, we report an unprecedented metal-free-catalyzed, chemodivergent and skeleton-controllable annulation reactions of o-HPEs with aryldiazonium salts. This protocol is featured by a new intermolecular chromone annulation strategy for the divergent synthesis of pyridazin-fused chromones via adjusting the reaction temperature. Moreover, the pyridazin-fused chromones exhibits promising high antiviral activity against human coronavirus OC43 (HCoV-OC43), with higher safety compared to reference drug (Arbidol), indicating that the intermolecular chromone annulation methodology might provide assistance for drug discovery.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":null,"pages":null},"PeriodicalIF":5.4,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141079191","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}
In this study, we conducted a theoretical investigation to clarify the mechanism of C–F bond activation using density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations, where Et3SiBpin and KOtBu serve as reaction partners. Results suggest that a reactive nucleophile KSiEt3 is generated in situ, which activates C(sp3)–F bond via a bimolecular nucleophilic substitution (SN2) with a lower energy barrier (23.6 kcal mol-1) than that (28.2 kcal mol-1) activates C(sp2)–F bond via a nucleophilic aromatic substitution reaction (SNAr). This is consistent with experimental result that silylation C(sp3)–F bond succeeded without Ni0-catalyst, while the C(sp2)–F bond did not. In the presence of Ni0(cod)2, a more reactive ate-complex K+[Ni0(cod)2(SiEt3)]– is generated via the strong coordination of (SiEt3)– anion to Ni0-center. The inert C(sp2)–F bond activation is thus succeeded via an unusual Ni0-mediated SNAr. Surprisingly, results show the activation energy (21.8 kcal mol-1) for nucleophilic attack by Ni0 center is significantly lower than that (36.2 kcal mol-1) by (SiEt3)– anion. Furthermore, the outer-sphere transition state is more stable than well-known inner-sphere one because radius of K+ is too large to form a multicomponent ring with synergistic stabilization. Except the Ni···Si coordination, this unpresented transition state of C(sp2)–F bond activation is stabilized through multiple non-covalent interactions. Additionally, AIMD simulations were employed to elucidate dynamic effect of Ni0(silyl)-ate complex initiated C(sp2)–F bond activation, highlighting the pivotal role of multiple non-covalent interactions in the reaction.
{"title":"Mechanistic study on C(sp2)–F bond activation by Ni0(silyl)-ate complex: an outer-sphere pathway via Ni0-mediated nucleophilic aromatic substitution","authors":"Xiao-Xia You, Jian-Sen Wang, Xiao-Xiao Li, Ling-Qi Meng, Rong-Lin Zhong, Zhong-Min Su","doi":"10.1039/d4qo00743c","DOIUrl":"https://doi.org/10.1039/d4qo00743c","url":null,"abstract":"In this study, we conducted a theoretical investigation to clarify the mechanism of C–F bond activation using density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations, where Et3SiBpin and KOtBu serve as reaction partners. Results suggest that a reactive nucleophile KSiEt3 is generated in situ, which activates C(sp3)–F bond via a bimolecular nucleophilic substitution (SN2) with a lower energy barrier (23.6 kcal mol-1) than that (28.2 kcal mol-1) activates C(sp2)–F bond via a nucleophilic aromatic substitution reaction (SNAr). This is consistent with experimental result that silylation C(sp3)–F bond succeeded without Ni0-catalyst, while the C(sp2)–F bond did not. In the presence of Ni0(cod)2, a more reactive ate-complex K+[Ni0(cod)2(SiEt3)]– is generated via the strong coordination of (SiEt3)– anion to Ni0-center. The inert C(sp2)–F bond activation is thus succeeded via an unusual Ni0-mediated SNAr. Surprisingly, results show the activation energy (21.8 kcal mol-1) for nucleophilic attack by Ni0 center is significantly lower than that (36.2 kcal mol-1) by (SiEt3)– anion. Furthermore, the outer-sphere transition state is more stable than well-known inner-sphere one because radius of K+ is too large to form a multicomponent ring with synergistic stabilization. Except the Ni···Si coordination, this unpresented transition state of C(sp2)–F bond activation is stabilized through multiple non-covalent interactions. Additionally, AIMD simulations were employed to elucidate dynamic effect of Ni0(silyl)-ate complex initiated C(sp2)–F bond activation, highlighting the pivotal role of multiple non-covalent interactions in the reaction.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":null,"pages":null},"PeriodicalIF":5.4,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141079319","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 first organocatalyzed asymmetric reductive amination strategy towards C−N axially chiral pentatomic heterobiaryls has been disclosed. The noncovalent n→π* interaction in the cyclic transition state plays a crucial role in ensuring the reaction to occur through a dynamic kinetic resolution process, leading to a series of N-arylindole atropisomers in good yields and enantioselectivities (up to 96% yield, 91% ee) under the influence of a chiral N-triflyl phosphoramide catalyst.
{"title":"Dynamic kinetic resolution of atropisomeric N-arylindoles via chiral N-triflyl phosphoramide catalyzed asymmetric reductive amination","authors":"You-Dong Shao, Dan-Dan Han, Hong-Xin Jiang, Xin-Yu Zhou, Wei-Kang Wang, Jia-Xi Zhang, Ya-Fei Liu, Dao-Juan Cheng","doi":"10.1039/d4qo00616j","DOIUrl":"https://doi.org/10.1039/d4qo00616j","url":null,"abstract":"The first organocatalyzed asymmetric reductive amination strategy towards C−N axially chiral pentatomic heterobiaryls has been disclosed. The noncovalent n→π* interaction in the cyclic transition state plays a crucial role in ensuring the reaction to occur through a dynamic kinetic resolution process, leading to a series of N-arylindole atropisomers in good yields and enantioselectivities (up to 96% yield, 91% ee) under the influence of a chiral N-triflyl phosphoramide catalyst.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":null,"pages":null},"PeriodicalIF":5.4,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141079293","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}
Yongdi Xin, Qianting Zhou, Bin Li, Biao Cheng, Xinying Zhang, Xuesen Fan
Presented herein is a concise synthesis of structurally diverse pyrazolo[1,2-a]pyrazolones based on condition-controlled divergent reactions of 1-arylpyrazolidinones with allenyl acetates. To be specific, mono C−H bond alkenylation-annulation or double C−H alkenylation-annulation could be realized selectively and effectively to furnish pyrazolo[1,2-a]pyrazolone scaffolds with distinct substitution patterns through simply regulating the reaction conditions. To our knowledge, such a controllable selective reaction pattern has not been disclosed previously. In addition, the products thus formed could be transformed into several value-added hybrid compounds through easy-to-run derivations by taking advantages of the rich chemistry of the functional groups in situ introduced. In general, these newly developed protocols feature simple substrates with broad scope, structurally diverse products, easily modulated selectivity, concise synthetic procedure, excellent step-economy and ready scalability.
{"title":"Synthesis of Structurally Diverse Pyrazolo[1,2-a]pyrazolones Based on Selective C−H Bond Alkenylation-Annulation of 1-Arylpyrazolidinones with Allenyl Acetates","authors":"Yongdi Xin, Qianting Zhou, Bin Li, Biao Cheng, Xinying Zhang, Xuesen Fan","doi":"10.1039/d4qo00701h","DOIUrl":"https://doi.org/10.1039/d4qo00701h","url":null,"abstract":"Presented herein is a concise synthesis of structurally diverse pyrazolo[1,2-a]pyrazolones based on condition-controlled divergent reactions of 1-arylpyrazolidinones with allenyl acetates. To be specific, mono C−H bond alkenylation-annulation or double C−H alkenylation-annulation could be realized selectively and effectively to furnish pyrazolo[1,2-a]pyrazolone scaffolds with distinct substitution patterns through simply regulating the reaction conditions. To our knowledge, such a controllable selective reaction pattern has not been disclosed previously. In addition, the products thus formed could be transformed into several value-added hybrid compounds through easy-to-run derivations by taking advantages of the rich chemistry of the functional groups in situ introduced. In general, these newly developed protocols feature simple substrates with broad scope, structurally diverse products, easily modulated selectivity, concise synthetic procedure, excellent step-economy and ready scalability.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":null,"pages":null},"PeriodicalIF":5.4,"publicationDate":"2024-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141079288","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}
Ruyi Li, Huaqin Wu, Junjie Bai, Zao Zhang, Pengcheng Lian, Muyang Zhu, Hang Liu, Xiaobing Wan
Sulfinimidate esters, despite their distinctive structural and biological properties, remain underexplored, primarily due to the paucity of information concerning their synthetic methodologies and structural diversity. Herein, we present a pioneering synthetic strategy for sulfinimidate esters that harnesses commercially available feedstock chemicals. The cornerstone of this modular approach lies in the employment of thiols as essential linchpins, facilitating oxidative coupling reactions with amines and alcohols. This methodology has facilitated the synthesis of an extensive array of sulfinimidate esters, showcasing a diverse collection that encompasses more than 150 distinct examples, notably featuring over 20 heterocyclic and carbocyclic variants. The versatility of this synthetic protocol is underscored by successful scale-up attempts and its application to the late-stage modification of intricate molecules. Consequently, our research not only advances the understanding of sulfinimidate esters by providing a robust synthetic pathway but also holds the potential to accelerate the assembly of molecule libraries for drug discovery.
{"title":"Modular Construction of Sulfinimidate Esters: Expanding Chemical Space and Enabling Late-Stage Diversification","authors":"Ruyi Li, Huaqin Wu, Junjie Bai, Zao Zhang, Pengcheng Lian, Muyang Zhu, Hang Liu, Xiaobing Wan","doi":"10.1039/d4qo00502c","DOIUrl":"https://doi.org/10.1039/d4qo00502c","url":null,"abstract":"Sulfinimidate esters, despite their distinctive structural and biological properties, remain underexplored, primarily due to the paucity of information concerning their synthetic methodologies and structural diversity. Herein, we present a pioneering synthetic strategy for sulfinimidate esters that harnesses commercially available feedstock chemicals. The cornerstone of this modular approach lies in the employment of thiols as essential linchpins, facilitating oxidative coupling reactions with amines and alcohols. This methodology has facilitated the synthesis of an extensive array of sulfinimidate esters, showcasing a diverse collection that encompasses more than 150 distinct examples, notably featuring over 20 heterocyclic and carbocyclic variants. The versatility of this synthetic protocol is underscored by successful scale-up attempts and its application to the late-stage modification of intricate molecules. Consequently, our research not only advances the understanding of sulfinimidate esters by providing a robust synthetic pathway but also holds the potential to accelerate the assembly of molecule libraries for drug discovery.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":null,"pages":null},"PeriodicalIF":5.4,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141069310","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}
Bisphosphonium salt catalyzed [3+2] annulation of N-tosylimino(iso)quinolinium ylides with aryl olefins under visible light has been developed, providing a series of β-aryl-substituted pyrazolo(iso)quinoline compounds with good regioselectivity. During this research, a new oxygen-free approach was developed to improve the synthetic efficiency of the bisphosphonium catalyst.
{"title":"Bisphosphonium salt catalyzed [3+2] annulation of N-tosylimino(iso)quinolinium ylides with aryl olefins under Blue LED Irradiation","authors":"Yu Wang, Lili Wang, Zheng Duan","doi":"10.1039/d4qo00700j","DOIUrl":"https://doi.org/10.1039/d4qo00700j","url":null,"abstract":"Bisphosphonium salt catalyzed [3+2] annulation of N-tosylimino(iso)quinolinium ylides with aryl olefins under visible light has been developed, providing a series of β-aryl-substituted pyrazolo(iso)quinoline compounds with good regioselectivity. During this research, a new oxygen-free approach was developed to improve the synthetic efficiency of the bisphosphonium catalyst.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":null,"pages":null},"PeriodicalIF":5.4,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141079291","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 C=C double bond cleavage of 2-cyanoaryl acrylamides through merging 2,3-butanedione and N-hydroxysuccinimide as visible-light-enabled hydrogen atom transfer catalysts is effectively established for generating functionalized 4-amino-2-quinolones under metal-free and redox neutral conditions. Detailed mechanism studies indicates that the solvent 1,3-dioxolane offers crucial 1,3-dioxolan-2-yl radical facilitated by the in-situ formed H-atom abstracting species, and 2-alkenyl-1,3-dioxolane is probably another product in this photocatalytic protocol.
{"title":"Merging 2,3-butanedione and N-hydroxysuccinimide as visible-light-enabled hydrogen atom transfer catalysts for C=C double bond cleavage of 2-cyanoaryl acrylamides toward 4-amino-2-quinolones","authors":"Jun Huang, Fengting Zhu, Jinlian Wen, Jiali Xu, Jing-Mei Yuan, Wenqiang Chen","doi":"10.1039/d4qo00458b","DOIUrl":"https://doi.org/10.1039/d4qo00458b","url":null,"abstract":"The C=C double bond cleavage of 2-cyanoaryl acrylamides through merging 2,3-butanedione and N-hydroxysuccinimide as visible-light-enabled hydrogen atom transfer catalysts is effectively established for generating functionalized 4-amino-2-quinolones under metal-free and redox neutral conditions. Detailed mechanism studies indicates that the solvent 1,3-dioxolane offers crucial 1,3-dioxolan-2-yl radical facilitated by the in-situ formed H-atom abstracting species, and 2-alkenyl-1,3-dioxolane is probably another product in this photocatalytic protocol.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":null,"pages":null},"PeriodicalIF":5.4,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141069305","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}
Fen Liu, Ji-Hong Gu, Zi-Yue Zhang, Qiong Zhan, Hai-Xia Yang, Yun Hu, Jin-Yan Zhang, Wei Tang, Wen-Cai Ye, Lei Wang
(+)/(−)-Xanthrysol A (1), an enantiomeric pair of novel macrocyclic meroterpenoids, along with three enantiomeric pairs of biogenetically related meroterpenoids (+)/(−)-xanthrysols B–D (2−4), were isolated and identified from the leaves of Xanthostemon chrysanthus. Structurally, compounds 1–4 are unique phenylpropanoyl-phloroglucinol-based meroterpenoids with three kinds of new carbon skeletons. Notably, xanthrysol A (1) features an unprecedented 6/6/16 fused ring system, incorporating a 2,4,16-trioxatricyclo[12.6.2.017,21]docosane core. Their structures with absolute configurations were established by comprehensive spectroscopic analyses, single-crystal X-ray diffraction, and quantum chemical calculations. A plausible biogenetic pathway for 1–4 was proposed. Moreover, xanthrysol A demonstrated potent antiviral activity against respiratory syncytial virus (RSV) and acyclovir-resistant strains of herpes simplex virus type 1 (HSV-1/106, HSV-1/Blue and HSV-1/153) with IC50 values ranging from 4.68 to 8.10 µM. Time-of-addition assays showed that compound 1 specifically acts on the early stages of the virus replication process in both RSV and HSV-1.
{"title":"Xanthrysols A−D, Novel Meroterpenoids with Antiviral Activities from Xanthostemon chrysanthus","authors":"Fen Liu, Ji-Hong Gu, Zi-Yue Zhang, Qiong Zhan, Hai-Xia Yang, Yun Hu, Jin-Yan Zhang, Wei Tang, Wen-Cai Ye, Lei Wang","doi":"10.1039/d4qo00520a","DOIUrl":"https://doi.org/10.1039/d4qo00520a","url":null,"abstract":"(+)/(−)-Xanthrysol A (1), an enantiomeric pair of novel macrocyclic meroterpenoids, along with three enantiomeric pairs of biogenetically related meroterpenoids (+)/(−)-xanthrysols B–D (2−4), were isolated and identified from the leaves of Xanthostemon chrysanthus. Structurally, compounds 1–4 are unique phenylpropanoyl-phloroglucinol-based meroterpenoids with three kinds of new carbon skeletons. Notably, xanthrysol A (1) features an unprecedented 6/6/16 fused ring system, incorporating a 2,4,16-trioxatricyclo[12.6.2.017,21]docosane core. Their structures with absolute configurations were established by comprehensive spectroscopic analyses, single-crystal X-ray diffraction, and quantum chemical calculations. A plausible biogenetic pathway for 1–4 was proposed. Moreover, xanthrysol A demonstrated potent antiviral activity against respiratory syncytial virus (RSV) and acyclovir-resistant strains of herpes simplex virus type 1 (HSV-1/106, HSV-1/Blue and HSV-1/153) with IC50 values ranging from 4.68 to 8.10 µM. Time-of-addition assays showed that compound 1 specifically acts on the early stages of the virus replication process in both RSV and HSV-1.","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":null,"pages":null},"PeriodicalIF":5.4,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141069250","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}
Man Zhang, Yifan Ru, Shilin Wang, Wen Fu, Tianyu Li, Xusheng Shao, Zhong Li and Wu-Lin Yang
An enantioselective cascade allylation/cyclization reaction of 1-(methylthio)-2-nitroenamines with 2-(1-hydroxyallyl)phenols was accomplished by using a chiral Ir(I) catalyst. A broad range of 2-amino-3-nitro-4H-chromene derivatives were obtained in moderate to high yields (55–99%) with moderate to excellent enantioselectivities (50–99% ee). Meanwhile, enantioenriched 2-amino-3-cyano-4H-chromene derivatives could be readily synthesized by using malononitrile in this cascade reaction. The antifungal activities of 2-amino-4H-chromene derivatives were investigated against four species of phytopathogenic fungi and a novel antifungal lead compound with good antifungal activity against Rhizoctonia solani (EC50 = 17.43 mg L−1) was found.
{"title":"Enantioselective synthesis of 2-amino-4H-chromene derivatives with antifungal activities on phytopathogenic fungi†","authors":"Man Zhang, Yifan Ru, Shilin Wang, Wen Fu, Tianyu Li, Xusheng Shao, Zhong Li and Wu-Lin Yang","doi":"10.1039/D4QO00686K","DOIUrl":"10.1039/D4QO00686K","url":null,"abstract":"<p >An enantioselective cascade allylation/cyclization reaction of 1-(methylthio)-2-nitroenamines with 2-(1-hydroxyallyl)phenols was accomplished by using a chiral Ir(<small>I</small>) catalyst. A broad range of 2-amino-3-nitro-4<em>H</em>-chromene derivatives were obtained in moderate to high yields (55–99%) with moderate to excellent enantioselectivities (50–99% ee). Meanwhile, enantioenriched 2-amino-3-cyano-4<em>H</em>-chromene derivatives could be readily synthesized by using malononitrile in this cascade reaction. The antifungal activities of 2-amino-4<em>H</em>-chromene derivatives were investigated against four species of phytopathogenic fungi and a novel antifungal lead compound with good antifungal activity against <em>Rhizoctonia solani</em> (EC<small><sub>50</sub></small> = 17.43 mg L<small><sup>−1</sup></small>) was found.</p>","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141069308","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}
In this study, we developed the first visible-light-induced phosphine-catalyzed radical cyclization of bromodifluoroacyl arenes with diverse alkenes, affording a variety of cyclic gem-difluoroacyl scaffolds in good to excellent yields. The strategy is highlighted by metal photocatalyst-free nature, mild reaction conditions and excellent functional group tolerance, and it is amenable to late-stage modification of complex molecules and gram-scale synthesis, and expands the reaction profiles of phosphine catalysis. Preliminary experimental and computational studies indicate that this reaction involves a radical process that is triggered by the photochemical activity of an electron donor–acceptor complex formed from bromodifluoroacyl and phosphine.
{"title":"Metal-free phosphine-catalyzed visible-light-induced radical cyclization of alkenes: access to cyclic gem-difluoroacyl scaffolds†","authors":"Ruowen Li, Yicong Li, Yiwei Liu, Yanzhao Wang, Jingjing Wu and Fanhong Wu","doi":"10.1039/D4QO00503A","DOIUrl":"10.1039/D4QO00503A","url":null,"abstract":"<p >In this study, we developed the first visible-light-induced phosphine-catalyzed radical cyclization of bromodifluoroacyl arenes with diverse alkenes, affording a variety of cyclic <em>gem</em>-difluoroacyl scaffolds in good to excellent yields. The strategy is highlighted by metal photocatalyst-free nature, mild reaction conditions and excellent functional group tolerance, and it is amenable to late-stage modification of complex molecules and gram-scale synthesis, and expands the reaction profiles of phosphine catalysis. Preliminary experimental and computational studies indicate that this reaction involves a radical process that is triggered by the photochemical activity of an electron donor–acceptor complex formed from bromodifluoroacyl and phosphine.</p>","PeriodicalId":97,"journal":{"name":"Organic Chemistry Frontiers","volume":null,"pages":null},"PeriodicalIF":4.6,"publicationDate":"2024-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141069301","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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