Photochemical Strain‐Release‐Driven Cyclobutylation of C(sp3)‐Centered Radicals

A new photoredox‐catalyzed decarboxylative radical addition approach to functionalized cyclobutanes is described. The reaction involves an unprecedented formal Giese‐type addition of C(sp3)‐centered radicals to highly strained bicyclo[1.1.0]butanes. The mild photoredox conditions, which make use of...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2020-02, Vol.59 (7), p.2618-2622
Main Authors: Ernouf, Guillaume, Chirkin, Egor, Rhyman, Lydia, Ramasami, Ponnadurai, Cintrat, Jean‐Christophe
Format: Article
Language:English
Subjects:
bicyclo[1.1.0]butanes
Butane
Butanes
Carboxylic acids
Chemical Sciences
cyclobutanes
late-stage functionalization
photocatalysis
Photochemicals
Radicals
strained molecules
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Summary:A new photoredox‐catalyzed decarboxylative radical addition approach to functionalized cyclobutanes is described. The reaction involves an unprecedented formal Giese‐type addition of C(sp3)‐centered radicals to highly strained bicyclo[1.1.0]butanes. The mild photoredox conditions, which make use of a readily available and bench stable phenyl sulfonyl bicyclo[1.1.0]butane, proved to be amenable to a diverse range of α‐amino and α‐oxy carboxylic acids, providing a concise route to 1,3‐disubstituted cyclobutanes. Furthermore, kinetic studies and DFT calculations unveiled mechanistic details on bicyclo[1.1.0]butane reactivity relative to the corresponding olefin system. High‐lying SOMO radicals, generated in situ under visible‐light photoredox conditions, undergo an efficient addition to highly strained bicyclo[1.1.0]butanes, providing a straightforward access to valuable alkylated cyclobutanes.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201908951