Haixing Zhang, Chaoyue Sun, Xuan Zhang, Xuan Cheng, Guiwen Guo, Wang Geng, Peiwei Gong, Shumiao Zhang, Mianran Chao, Duyi Shen
{"title":"C–N cleavage of secondary amide to access primary amide by a Co(II)/Oxone oxidation system","authors":"Haixing Zhang, Chaoyue Sun, Xuan Zhang, Xuan Cheng, Guiwen Guo, Wang Geng, Peiwei Gong, Shumiao Zhang, Mianran Chao, Duyi Shen","doi":"10.1039/d4ob00974f","DOIUrl":null,"url":null,"abstract":"Cleavage of the C–N bond of a secondary amide could provide alternative access to primary amides; however, this strategy remains challenging due to oxidation resistance of the amide. Herein, we employed the cobalt(<small>II</small>)/Oxone catalytic system, one of the advanced oxidation processes (AOPs), to make it available to break the strong C–N bond of various secondary (sulfon)amides, especially those bearing electron-poor or <em>ortho</em>-substituted <em>N</em>-arenes, <em>en route</em> to desirable primary (sulfon)amides. Control experiments showed that it was probably not the generally-considered persulfate anion radical in the cobalt/peroxymonosulfate (Co/PMS) system but the proposed high-valent cobalt-oxo intermediate that should be the major active species for the initial N–H oxidation of <em>N</em>-aryl amides. In the case of <em>N</em>-alkylated secondary amides, the α-C–H bond, rather than the N–H bond, should be oxidized first by both the reactive radicals and high-valent cobalt-oxo species. This work not only establishes an efficient method for removing the <em>N</em>-substituents of secondary amides at low cost, with readily available and eco-friendly reagents, but also demonstrates further synthetic application and provides more insight into intermediates for metal-based AOPs in environmental remediation.","PeriodicalId":96,"journal":{"name":"Organic & Biomolecular Chemistry","volume":null,"pages":null},"PeriodicalIF":2.9000,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Organic & Biomolecular Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1039/d4ob00974f","RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, ORGANIC","Score":null,"Total":0}
引用次数: 0
Abstract
Cleavage of the C–N bond of a secondary amide could provide alternative access to primary amides; however, this strategy remains challenging due to oxidation resistance of the amide. Herein, we employed the cobalt(II)/Oxone catalytic system, one of the advanced oxidation processes (AOPs), to make it available to break the strong C–N bond of various secondary (sulfon)amides, especially those bearing electron-poor or ortho-substituted N-arenes, en route to desirable primary (sulfon)amides. Control experiments showed that it was probably not the generally-considered persulfate anion radical in the cobalt/peroxymonosulfate (Co/PMS) system but the proposed high-valent cobalt-oxo intermediate that should be the major active species for the initial N–H oxidation of N-aryl amides. In the case of N-alkylated secondary amides, the α-C–H bond, rather than the N–H bond, should be oxidized first by both the reactive radicals and high-valent cobalt-oxo species. This work not only establishes an efficient method for removing the N-substituents of secondary amides at low cost, with readily available and eco-friendly reagents, but also demonstrates further synthetic application and provides more insight into intermediates for metal-based AOPs in environmental remediation.