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Klimkait, Michael ; Berg, Nele ; Gschwind, Ruth M. ; Zeitler, Kirsten

PCET beyond Simple pKa-Related Base Effects: Unlocking Inaccessible Substrates for Direct Intermolecular Photocatalytic Ring-Opening Remote Alkylative C-C Functionalization of Cycloalkanols Version 2

Klimkait, Michael, Berg, Nele, Gschwind, Ruth M. und Zeitler, Kirsten (2025) PCET beyond Simple pKa-Related Base Effects: Unlocking Inaccessible Substrates for Direct Intermolecular Photocatalytic Ring-Opening Remote Alkylative C-C Functionalization of Cycloalkanols Version 2. ChemRxiv.

Veröffentlichungsdatum dieses Volltextes: 23 Jul 2025 06:53
Artikel
DOI zum Zitieren dieses Dokuments: 10.5283/epub.77249


Zusammenfassung

Oxidative multisite proton-coupled electron transfer (MS-PCET) reactions, particularly those occurring under metal-free pho¬to¬catalytic conditions using visible light, have emerged as a promising tool for the activation of strong O-H bonds in (cyclo)alkanols. However, these methods generally require the use of e-rich arene-containing derivatives (para-methoxyphenyl (PMP), etc.) – a factor that ...

Oxidative multisite proton-coupled electron transfer (MS-PCET) reactions, particularly those occurring under metal-free pho¬to¬catalytic conditions using visible light, have emerged as a promising tool for the activation of strong O-H bonds in (cyclo)alkanols. However, these methods generally require the use of e-rich arene-containing derivatives (para-methoxyphenyl (PMP), etc.) – a factor that greatly restricts their broader applicability. Herein, we report the successful implementation of targeted modulation of the base partner in photocatalytic cascade reactions of cyclic alcohols, unlocking previously inaccessible, non-activated substrates. This approach successfully circumvents the prevalent limitations of ring-opening transformations of cycloalkanols by deliberately promoting base-alcohol interactions. As a result, we here demonstrate a general, operationally simple and widely applicable protocol for the redox-neutral transformations of cycloalkanols into terminally C(sp3)-C(sp3)-coupled, functionalized open-chain products. NMR-based mechanistic studies, comprising in-depth H-bond analysis and DOSY experiments, have elucidated the crucial role of the (pyridine) base in this multisite PCET, which surpasses typical pKa-related and/or steric effects. Ultimately, our gained insights into the key importance of additional weak interactions in promoting a pivotal productive alcohol-base pre-organization were directly put into practice to successfully pioneer remote alkylative Giese-type C-C-bond formations of previously challenging alkyl-substituted cycloalkanols.



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Details

DokumentenartArtikel
Titel eines Journals oder einer ZeitschriftChemRxiv
Buchtitel:PCET beyond Simple pKa-Related Base Effects: Unlocking Inaccessible Substrates for Direct Intermolecular Photocatalytic Ring-Opening Remote Alkylative C-C Functionalization of Cycloalkanols
Datum2025
Zusätzliche Informationen (Öffentlich)Version Notes- updated version incl. Supporting Material
InstitutionenChemie und Pharmazie > Institut für Organische Chemie > Arbeitskreis Prof. Dr. Ruth Gschwind
Projekte
Gefördert von: Deutsche Forschungsgemeinschaft (DFG) (444632635)
Identifikationsnummer
WertTyp
10.26434/chemrxiv-2025-j62j0-v2DOI
Stichwörter / Keywordsphotoredox catalysis, alkoxy radical, NMR, H-bonds, remote functionalization, cycloalkanols, PCET
Dewey-Dezimal-Klassifikation500 Naturwissenschaften und Mathematik > 540 Chemie
StatusVeröffentlicht
BegutachtetNein, diese Version wurde noch nicht begutachtet (bei preprints)
An der Universität Regensburg entstandenZum Teil
URN der UB Regensburgurn:nbn:de:bvb:355-epub-772499
Dokumenten-ID77249

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