Synlett 2024; 35(09): 1047-1051
DOI: 10.1055/a-2219-6907
cluster
Chemical Synthesis and Catalysis in Germany

Visible-Light-Mediated Selective Allylic C–H Oxygenation of Cycloalkenes

Tabea Rohlfs
a   University of Münster, Organic Chemistry Institute, Corrensstraße 36/40, 48149 Münster, Germany
,
Leon Gerken
a   University of Münster, Organic Chemistry Institute, Corrensstraße 36/40, 48149 Münster, Germany
,
Jose L. Nova-Fernández
b   Organic Chemistry Department (Módulo 1), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
,
Sara Malagón
a   University of Münster, Organic Chemistry Institute, Corrensstraße 36/40, 48149 Münster, Germany
,
Mustafa Uygur
a   University of Münster, Organic Chemistry Institute, Corrensstraße 36/40, 48149 Münster, Germany
,
Silvia Cabrera
c   Inorganic Chemistry Department (Módulo 7), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
d   Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
,
José Alemán
b   Organic Chemistry Department (Módulo 1), Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
d   Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
,
Olga García Mancheño
a   University of Münster, Organic Chemistry Institute, Corrensstraße 36/40, 48149 Münster, Germany
› Institutsangaben
This work was funded by the Deutsche Forschungsgemeinschaft (DFG) within the projects GA 1594/6-2, GA 1594/7-1, and GRK 2678–437785492, and the DFG is gratefully acknowledged for this generous support. This work was also supported by the Spanish Ministry of Science and Innovation (project PID2021-122299NB-I00, TED2021-130470B-I00, TED2021-129999B-C32), the Comunidad de Madrid for European Structural Funds (S2018/NMT-4367) and proyectos sinérgicos I+D (Y2020/NMT-6469). We want to thank the ERASMUS+ and the ERASMUS program for enabling T.R. to do a research stay at U.A.M. and S.M. to conduct Master’s thesis work at the University of Münster, respectively. T.R. also thanks the IRTG 2678 for a PhD contract.


Abstract

A visible-light-mediated selective allylic C–H bond oxygenation of cyclic olefins is presented. Hence, the selective, mild monooxygenation of simple cycloalkenes has been achieved using an acridinium photoredox catalyst in combination with a phosphate base and a disulfide HAT reagent under air atmosphere at room temperature. The combination of both photocatalyst and HAT reagent, which can operate through a single or two different concurrent mechanistic pathways for the formation of the allyl radical, proved highly efficient, while the reaction with exclusively one or the other mediator performs in significantly lower yields. The formed allyl radical further reacts with a molecule of oxygen to build the corresponding peroxyradical that can abstract a hydrogen atom of another cycloalkene substrate, generating the known hydroperoxide intermediate in the formation of the ketone moiety. The advantages of this method rely on the easy use of air as oxygen source, as well as the selective monooxygenation of cycloalkenes without substitution in one of the allylic positions. Besides simple cyclic olefins, the method was also successfully applied in the oxidation of natural products such as the terpene valencene or cholesterol derivatives.

Supporting Information



Publikationsverlauf

Eingereicht: 03. Oktober 2023

Angenommen nach Revision: 29. November 2023

Accepted Manuscript online:
29. November 2023

Artikel online veröffentlicht:
05. Januar 2024

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