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Synthesis of Benzo-Fused Cyclic Ketones via Metal-Free Ring Expansion of Cyclopropanols Enabled by Proton-Coupled Electron Transfer

Tomohiro Kikuchi, Keiji Yamada, Takeshi Yasui* and Yoshihiko Yamamoto*

*Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho Chikusa, Nagoya 464-8603, Japan, Email:,

T. Kikuchi, K. Yamada, T. Yasui, Y. Yamaoto, Org. Lett., 2021, 23, 4710-4714.

DOI: 10.1021/acs.orglett.1c01436

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A proton-coupled electron transfer mediated by an organic photoredox catalyst enables a metal-free ring expansion of cyclopropanols containing a pendant styrene moiety to provide 1-tetralone and 1-benzosuberone derivatives depending on the substitution pattern of the alkene moiety.

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proposed mechanism


Key Words

tetralones, benzosuberones, photochemistry

ID: J54-Y2021