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Updated: Jul 15, 2025

[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
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[DPEPhosbcpCu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

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フォトレドックスラセミゼーションによって可能になったエナチオコンバージェント6π電循環

Sebastijan Ričko1,2, René Slot Bitsch1, Mikk Kaasik1

  • 1Department of Chemistry, Aarhus University, DK-8000 Aarhus C, Denmark.

Journal of the American Chemical Society
|September 27, 2023
PubMed
まとめ

この研究は,ラセミック・グリシネートからキラル・ベンゾクサジンを生成するための新しい触媒方法を導入している. フォトレドックスとルイス酸触媒を組み合わせた二重触媒システムは,オキサ-6π電循環によるエナチオコンバージェント合成を可能にします.

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Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
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The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
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Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
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