We report an unconventional I2-catalyzed cascade reaction for the synthesis of angular triquinane derivatives with a fused heterocycle skeleton, leveraging enaminones and anilines as simple acyclic precursors. The key to success lies in I2 functioning as a polar-reversal catalyst, which alters the reactivity at the α-position of the enaminone and facilitates the first hexa-functionalization of an enaminone along with the formation of highly congested continuous stereocenters.
{"title":"Iodine as Polarity-Reversal Catalyst: Synthesis of a Fused Heterocycle with Contiguous Stereocenters","authors":"Li-Sheng Wang, Yu-Man Song, You Zhou, Yong-Xing Tang, Chun-Yan Wu, Zhi-Cheng Yu, Hui Zhou, Kai-Lu Zheng, An-Xin Wu","doi":"10.1021/acs.orglett.4c03936","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c03936","url":null,"abstract":"We report an unconventional I<sub>2</sub>-catalyzed cascade reaction for the synthesis of angular triquinane derivatives with a fused heterocycle skeleton, leveraging enaminones and anilines as simple acyclic precursors. The key to success lies in I<sub>2</sub> functioning as a polar-reversal catalyst, which alters the reactivity at the α-position of the enaminone and facilitates the first hexa-functionalization of an enaminone along with the formation of highly congested continuous stereocenters.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"75 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858140","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}
Page 7820. The Strategic Leading Science and Technology Project of Chinese Academy of Sciences grant was incorrectly referenced as E4JD250301; the correct number is XDC0120102. The full correct Acknowledgment is in this Correction. This study was supported by the Strategic Leading Science and Technology Project of Chinese Academy of Sciences (grant no. XDC0120102), National Key Research and Development Program of China (grant no. 2019YFA0905100 to S.G.), and the Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project (TSBICIP-CXRC-062 to S.G. and TSBICIP-CXRC-069 to C.C.). This article has not yet been cited by other publications.
{"title":"Correction to “Synthetic Nicotinamide Cofactors as Alternatives to NADPH in Imine Reductase-Catalyzed Reactions”","authors":"Wei Kang, Shushan Gao, Jinping Bao, Lujia Yang, Yaqing Ma, Pingyuan Wang, Chang-Yun Wang, Chengsen Cui","doi":"10.1021/acs.orglett.4c04624","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04624","url":null,"abstract":"Page 7820. The Strategic Leading Science and Technology Project of Chinese Academy of Sciences grant was incorrectly referenced as E4JD250301; the correct number is XDC0120102. The full correct Acknowledgment is in this Correction. This study was supported by the Strategic Leading Science and Technology Project of Chinese Academy of Sciences (grant no. XDC0120102), National Key Research and Development Program of China (grant no. 2019YFA0905100 to S.G.), and the Tianjin Synthetic Biotechnology Innovation Capacity Improvement Project (TSBICIP-CXRC-062 to S.G. and TSBICIP-CXRC-069 to C.C.). This article has not yet been cited by other publications.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"18 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858053","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 : 2024-12-20DOI: 10.1021/acs.orglett.4c04127
Anamika Dhami, Sanoop P. Chandrasekharan, Kishor Mohanan
A Lewis acid-mediated C2-N-trifluoroethylamidation of quinolines, employing quinoline N-oxides, trifluorodiazoethane, and acetonitrile to forge a new class of N-(quinolin-2-yl)-N-(trifluoroethyl)acetamide is presented in this Letter. The reaction proceeds through a carbene generation/nitrile ylide formation/(3 + 2) cycloaddition/rearrangement cascade to furnish quinoline-2-N-(trifluoroethyl)acetamide derivatives in high yields.
{"title":"BF3-Mediated C2-Amidation of Quinoline N-Oxides Employing Trifluorodiazoethane and Acetonitrile: Access to 2-N-(Trifluoroethyl)amidoquinolines","authors":"Anamika Dhami, Sanoop P. Chandrasekharan, Kishor Mohanan","doi":"10.1021/acs.orglett.4c04127","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04127","url":null,"abstract":"A Lewis acid-mediated C2-<i>N-</i>trifluoroethylamidation of quinolines, employing quinoline <i>N-</i>oxides, trifluorodiazoethane, and acetonitrile to forge a new class of <i>N-</i>(quinolin<i>-</i>2-yl)-<i>N-</i>(trifluoroethyl)acetamide is presented in this Letter. The reaction proceeds through a carbene generation/nitrile ylide formation/(3 + 2) cycloaddition/rearrangement cascade to furnish quinoline-2-<i>N-</i>(trifluoroethyl)acetamide derivatives in high yields.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"31 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142867616","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 : 2024-12-20DOI: 10.1021/acs.orglett.4c04388
Kanta Shimotai, Ozora Sasamoto, Masanori Shigeno
In this paper, we report that the use of an alkyl silyl carbonate reagent combined with CsF and 18-crown-6 facilitates efficient direct carboxylations of (hetero)aromatic C–H bonds. This system also enables benzylic carboxylation of a toluene derivative and double carboxylation of methyl heteroarene. The carbonate reagent is characterized by its ease of handling and storage. Moreover, we demonstrate the application of this system in 13C-labeling experiments.
{"title":"Carboxylations of (Hetero)Aromatic C–H Bonds Using an Alkyl Silyl Carbonate Reagent","authors":"Kanta Shimotai, Ozora Sasamoto, Masanori Shigeno","doi":"10.1021/acs.orglett.4c04388","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04388","url":null,"abstract":"In this paper, we report that the use of an alkyl silyl carbonate reagent combined with CsF and 18-crown-6 facilitates efficient direct carboxylations of (hetero)aromatic C–H bonds. This system also enables benzylic carboxylation of a toluene derivative and double carboxylation of methyl heteroarene. The carbonate reagent is characterized by its ease of handling and storage. Moreover, we demonstrate the application of this system in <sup>13</sup>C-labeling experiments.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"31 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857681","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}
Kdn is a common member of the sialic acid family. Carbohydrates containing Kdn residues are widely distributed in nature and embody important biological information. However, the methods for synthesizing Kdn glycosides are limited, which restricts their biological study. In this paper, we developed efficient α- and β-stereoselective Kdn glycosylation methods by employing differentially protected Kdn thioglycoside donors under their respective activating protocols. The 5,7-O-carbonate fused Kdn thioglycoside 1a could be promoted with NIS/TfOH (cat.) in CH2Cl2/CH3CN (2:1) to afford Kdn glycosides with excellent α-selectivity in high yields. Meanwhile, based on the Ph2SO/Tf2O preactivation strategy, the nonfused Kdn thioglycoside 1b behaved as a high-yielding and β-selective donor to couple with various carbohydrate alcohols, leading to formation of β-Kdn glycosides. The synthetic utility of these newly developed glycosyl donors has been demonstrated by the stereoselective and straightforward assembly of two natural Kdn-containing oligosaccharides.
{"title":"Effect of Protecting Groups and Activating Conditions on 3-Deoxy-d-glycero-d-galacto-2-nonulosonic Acid (Kdn) Glycosylation: Stereoselective Synthesis of α- and β-Kdn Glycosides","authors":"Jin-Song Yang, Yu-Xiong Ruan, Hong-Yang Wang, Ling Li, Yan-Li Zhao, Yong Qin","doi":"10.1021/acs.orglett.4c04325","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04325","url":null,"abstract":"Kdn is a common member of the sialic acid family. Carbohydrates containing Kdn residues are widely distributed in nature and embody important biological information. However, the methods for synthesizing Kdn glycosides are limited, which restricts their biological study. In this paper, we developed efficient α- and β-stereoselective Kdn glycosylation methods by employing differentially protected Kdn thioglycoside donors under their respective activating protocols. The 5,7-<i>O</i>-carbonate fused Kdn thioglycoside <b>1a</b> could be promoted with NIS/TfOH (cat.) in CH<sub>2</sub>Cl<sub>2</sub>/CH<sub>3</sub>CN (2:1) to afford Kdn glycosides with excellent α-selectivity in high yields. Meanwhile, based on the Ph<sub>2</sub>SO/Tf<sub>2</sub>O preactivation strategy, the nonfused Kdn thioglycoside <b>1b</b> behaved as a high-yielding and β-selective donor to couple with various carbohydrate alcohols, leading to formation of β-Kdn glycosides. The synthetic utility of these newly developed glycosyl donors has been demonstrated by the stereoselective and straightforward assembly of two natural Kdn-containing oligosaccharides.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"86 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857831","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}
This study presents the indium-mediated three-component radical Reformatsky-type allylation of N-tert-butanesulfinyl iminoester with 1,3-butadiene. This novel approach offers a rapid synthesis pathway to valuable homoallylic noncanonical amino acids, demonstrated with over 30 examples showing nice regio- and diastereoselectivity. Mechanism studies revealed that allylindium complexes served as key intermediates, formed through a single-electron reduction of allylic radicals by Indium species.
{"title":"Indium Mediated Reformatsky-Type Allylation of N-tert-Butanesulfinyl Iminoester with 1,3-Butadiene","authors":"Shuangjie Lin, Renxu Cao, Zhixian Wu, Yihe Zhu, Shaohua Zhang, Xuehan Qi, Qingyu Shi, Yizhe Mao, Yunhe Jin, Erjun Hao, Lei Shi","doi":"10.1021/acs.orglett.4c04086","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04086","url":null,"abstract":"This study presents the indium-mediated three-component radical Reformatsky-type allylation of <i>N</i>-<i>tert</i>-butanesulfinyl iminoester with 1,3-butadiene. This novel approach offers a rapid synthesis pathway to valuable homoallylic noncanonical amino acids, demonstrated with over 30 examples showing nice regio- and diastereoselectivity. Mechanism studies revealed that allylindium complexes served as key intermediates, formed through a single-electron reduction of allylic radicals by Indium species.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"61 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857830","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 : 2024-12-20DOI: 10.1021/acs.orglett.4c04491
Kunlong Li, Hongjie Zhu, Changli Sun, Ge Tian, Xuan Ma, Pachaiyappan Saravana Kumar, Xiang Weng, Hu Yang, Runping Fang, Weilong Liu, Zhuo Shang, Junying Ma, Jianhua Ju
Metabolic blockade-based genome mining of the marine sediment-derived Saccharopolyspora erythraea SCSIO 07745 led to the discovery of 11 novel aminoquinolinone alkaloids, oxazoquinolinones A–J (1–10), characterized by an oxazolidone[3,2-α]quinoline-5,8-dione scaffold, and oxazoquinolinone K (11), featuring an unprecedented fused 6/6/6/5 tetracyclic core ring system. Additionally, 5 new biosynthetic intermediates or shunt products (12–16) and a known metabolite sannanine (17) were identified. Their structures were elucidated by extensive spectroscopic analyses and a comparison of electronic circular dichroism and single-crystal X-ray diffraction. On the basis of the functional gene analyses and structures of the intermediates or shunt products, plausible biosynthetic pathways for compounds 1–17 were proposed. Additionally, oxazoquinolinone K (11) obviously inhibited cell invasion of human glioma cell line LN229 cells at 10 μM.
{"title":"Metabolic Blockade-Based Genome Mining of Saccharopolyspora erythraea SCSIO 07745: Discovery and Biosynthetic Pathway of Aminoquinolinone Alkaloids Bearing 6/6/5 Tricyclic and 6/6/6/5 Tetracyclic Scaffolds","authors":"Kunlong Li, Hongjie Zhu, Changli Sun, Ge Tian, Xuan Ma, Pachaiyappan Saravana Kumar, Xiang Weng, Hu Yang, Runping Fang, Weilong Liu, Zhuo Shang, Junying Ma, Jianhua Ju","doi":"10.1021/acs.orglett.4c04491","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c04491","url":null,"abstract":"Metabolic blockade-based genome mining of the marine sediment-derived <i>Saccharopolyspora erythraea</i> SCSIO 07745 led to the discovery of 11 novel aminoquinolinone alkaloids, oxazoquinolinones A–J (<b>1</b>–<b>10</b>), characterized by an oxazolidone[3,2-α]quinoline-5,8-dione scaffold, and oxazoquinolinone K (<b>11</b>), featuring an unprecedented fused 6/6/6/5 tetracyclic core ring system. Additionally, 5 new biosynthetic intermediates or shunt products (<b>12</b>–<b>16</b>) and a known metabolite sannanine (<b>17</b>) were identified. Their structures were elucidated by extensive spectroscopic analyses and a comparison of electronic circular dichroism and single-crystal X-ray diffraction. On the basis of the functional gene analyses and structures of the intermediates or shunt products, plausible biosynthetic pathways for compounds <b>1</b>–<b>17</b> were proposed. Additionally, oxazoquinolinone K (<b>11</b>) obviously inhibited cell invasion of human glioma cell line LN229 cells at 10 μM.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"86 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142858065","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 : 2024-12-19DOI: 10.1021/acs.orglett.4c03458
Mathias Christmann
A Python script for the systematic, high-throughput analysis of accurate mass data was developed and tested on more than 3000 Supporting Information (SI) PDFs from Organic Letters. For each SI file, quadruplets of molecular formula, measured ion, e.g., [M + Na]+, and reported calculated and found masses were extracted and analyzed. Interestingly, only 40% of the files containing readable accurate mass data were both internally consistent and in compliance with The ACS Guide to Scholarly Communication. The analysis revealed unexpected errors and provided actionable advice on how to improve data quality.
{"title":"What I Learned from Analyzing Accurate Mass Data of 3000 Supporting Information Files","authors":"Mathias Christmann","doi":"10.1021/acs.orglett.4c03458","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c03458","url":null,"abstract":"A Python script for the systematic, high-throughput analysis of accurate mass data was developed and tested on more than 3000 Supporting Information (SI) PDFs from <i>Organic Letters</i>. For each SI file, quadruplets of molecular formula, measured ion, e.g., [M + Na]<sup>+</sup>, and reported calculated and found masses were extracted and analyzed. Interestingly, only 40% of the files containing readable accurate mass data were both internally consistent and in compliance with <i>The ACS Guide to Scholarly Communication</i>. The analysis revealed unexpected errors and provided actionable advice on how to improve data quality.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"40 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857833","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 : 2024-12-19DOI: 10.1021/acs.orglett.4c03980
Molhm Nassir, Luca Gherardi, Richard L. Redman, Yonghao Jin, Feng Yao, Yang Yang, Nicholas Raheja, Arjun Natarajan, David Butler, Kyle W. Knouse, Phil S. Baran
Three critical advances in simplifying the adoption of P(V)-based stereopure, phosphorothioate-containing oligonucleotide synthesis are reported. A more inexpensive phosphorus–sulfur incorporation reagent (ΨBr) is introduced, a robust linker system was developed, and a systematic study of common nucleobase protecting groups was performed to significantly reduce the barrier to adoption of this technology.
{"title":"An Improved P(V) Thio-Oligonucleotide Synthesis Platform","authors":"Molhm Nassir, Luca Gherardi, Richard L. Redman, Yonghao Jin, Feng Yao, Yang Yang, Nicholas Raheja, Arjun Natarajan, David Butler, Kyle W. Knouse, Phil S. Baran","doi":"10.1021/acs.orglett.4c03980","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c03980","url":null,"abstract":"Three critical advances in simplifying the adoption of P(V)-based stereopure, phosphorothioate-containing oligonucleotide synthesis are reported. A more inexpensive phosphorus–sulfur incorporation reagent (<b>Ψ</b><sup><b>Br</b></sup>) is introduced, a robust linker system was developed, and a systematic study of common nucleobase protecting groups was performed to significantly reduce the barrier to adoption of this technology.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"97 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142857835","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}
Developing asymmetric transformations using electroredox and N-heterocyclic carbene (NHC)-catalyzed radical pathways is still desirable and challenging. Herein, we report an iodide-promoted β-carbon activation (LUMO-lowering process) of enals via electroredox carbene catalysis coupled with a hydrogen evolution reaction (HER). This strategy offers an environmentally friendly and sustainable route for rapidly assembling synthetically useful chiral naphthopyran-3-one in good to excellent yield and enantioselectivity using traceless electrons as inexpensive and greener oxidants. The mechanistic studies and cyclic voltammetry suggest that the reaction proceeds via direct single electron transfer (SET) of the in situ-generated Breslow intermediate.
{"title":"Electroredox N-Heterocyclic Carbene-Catalyzed Enantioselective (3 + 3) Annulation of Enals with 2-Naphthols","authors":"Vikas Kale, Sayan Shee, Shiv Dutt, Nidhi Sinha, Akkattu T. Biju, Prabal Banerjee","doi":"10.1021/acs.orglett.4c03879","DOIUrl":"https://doi.org/10.1021/acs.orglett.4c03879","url":null,"abstract":"Developing asymmetric transformations using electroredox and N-heterocyclic carbene (NHC)-catalyzed radical pathways is still desirable and challenging. Herein, we report an iodide-promoted β-carbon activation (LUMO-lowering process) of enals via electroredox carbene catalysis coupled with a hydrogen evolution reaction (HER). This strategy offers an environmentally friendly and sustainable route for rapidly assembling synthetically useful chiral naphthopyran-3-one in good to excellent yield and enantioselectivity using traceless electrons as inexpensive and greener oxidants. The mechanistic studies and cyclic voltammetry suggest that the reaction proceeds via direct single electron transfer (SET) of the in situ-generated Breslow intermediate.","PeriodicalId":54,"journal":{"name":"Organic Letters","volume":"23 1","pages":""},"PeriodicalIF":5.2,"publicationDate":"2024-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142849697","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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