{"title":"Cooperative Ligand-Enabled Facile Synthesis of γ-C(sp3)–H Alkenylated Aliphatic Amides: A Comprehensive Protocol to Free N–H Tolerance","authors":"Suparna Dutta, Nikunj Kumar, Minhajul Islam, Wajid Ali, Puneet Gupta, Debabrata Maiti","doi":"10.1021/acscatal.4c07905","DOIUrl":null,"url":null,"abstract":"Site-selective distal C(<i>sp<sup>3</sup></i>)–H functionalization of aliphatic amides is one of the longstanding challenges in synthetic methodology. Herein, we report a palladium-catalyzed <i>γ</i>-C(<i>sp<sup>3</sup></i>)–H alkenylation of native aliphatic amide, exploiting a cooperative ligand approach to harness the weak coordinating ability of the amide functional group. Apart from tertiary amides, the protocol developed by us is also suitable for secondary, primary, and relatively unbiased <i>β</i>-C–H bond-containing amides, which remain unexplored till date. Theoretical calculations revealed that the combination of ligands is crucial for the reaction. Monoprotected amino acid (MPAA) ligand is essential for the concerted metalation–deprotonation (CMD) step of the C–H activation, occurring <i>via</i> a distinctive [5,6]-palladacyclic transition state. Meanwhile, the pyridone ligand plays a key role in forming the catalyst resting state, promoting <i>β</i>-hydride elimination, and facilitating product release. Both experimental and computational mechanistic studies confirm that C–H activation is the rate-limiting step in this process, providing crucial insights into the factors governing regioselective functionalization at the distant <i>γ</i>-site.","PeriodicalId":9,"journal":{"name":"ACS Catalysis ","volume":"136 3 1","pages":""},"PeriodicalIF":11.3000,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"ACS Catalysis ","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1021/acscatal.4c07905","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
Abstract
Site-selective distal C(sp3)–H functionalization of aliphatic amides is one of the longstanding challenges in synthetic methodology. Herein, we report a palladium-catalyzed γ-C(sp3)–H alkenylation of native aliphatic amide, exploiting a cooperative ligand approach to harness the weak coordinating ability of the amide functional group. Apart from tertiary amides, the protocol developed by us is also suitable for secondary, primary, and relatively unbiased β-C–H bond-containing amides, which remain unexplored till date. Theoretical calculations revealed that the combination of ligands is crucial for the reaction. Monoprotected amino acid (MPAA) ligand is essential for the concerted metalation–deprotonation (CMD) step of the C–H activation, occurring via a distinctive [5,6]-palladacyclic transition state. Meanwhile, the pyridone ligand plays a key role in forming the catalyst resting state, promoting β-hydride elimination, and facilitating product release. Both experimental and computational mechanistic studies confirm that C–H activation is the rate-limiting step in this process, providing crucial insights into the factors governing regioselective functionalization at the distant γ-site.
期刊介绍:
ACS Catalysis is an esteemed journal that publishes original research in the fields of heterogeneous catalysis, molecular catalysis, and biocatalysis. It offers broad coverage across diverse areas such as life sciences, organometallics and synthesis, photochemistry and electrochemistry, drug discovery and synthesis, materials science, environmental protection, polymer discovery and synthesis, and energy and fuels.
The scope of the journal is to showcase innovative work in various aspects of catalysis. This includes new reactions and novel synthetic approaches utilizing known catalysts, the discovery or modification of new catalysts, elucidation of catalytic mechanisms through cutting-edge investigations, practical enhancements of existing processes, as well as conceptual advances in the field. Contributions to ACS Catalysis can encompass both experimental and theoretical research focused on catalytic molecules, macromolecules, and materials that exhibit catalytic turnover.