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Updated: Jun 14, 2025
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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Visible-Light-Induced Generation of p-Quinone Methides via Paternò-Büchi Reaction: Access to Quaternary Centers
Mitsumi Takeda1, Saki Maejima1, Eiji Yamaguchi1,2
1Laboratory of Pharmaceuticals Synthetic Chemistry, Gifu Pharmaceutical University, 1-25-4, Daigaku-nishi, Gifu 501-1196, Japan.
Abstract:
A visible-light-mediated [2+2] Paternò-Büchi cycloaddition between p-benzoquinone and terminal and internal alkynes enables in situ generation of minimally substituted p-quinone methides (pQM). Subsequent 1,6-conjugate addition with diverse alcoholic nucleophiles forms quaternary centers under mild, metal-free conditions. Mechanistic investigations support a photocatalyst-independent pathway involving oxetene formation and electrocyclic ring opening, expanding the utility of pQM intermediates in complex molecule construction.
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