Photoredox-Catalyzed Formal [4 + 2] Cycloaddition of Pyridinium Masked Enols with Unactivated Olefins
Herein, we developed a photoredox-catalyzed formal [4 + 2] cycloaddition of pyridinium-masked enols with unactivated olefins utilizing Ir(dF(Me)ppy)<sub>2</sub>(dtbbpy)PF<sub>6</sub> as catalyst under blue light (455 nm) irradiation. A variety of pyridinium-masked enols and unactivated alkenes were examined to synthesize tetralones under optimal conditions. Through control and deuterium labeling experiments, it was suggested that the <i>in situ</i> generated α-carbon radical first attacked the alkene, forming a γ-carbonyl radical intermediate. This intermediate subsequently underwent intramolecular radical cyclization and deprotonation to produce the desired tetralones. This protocol facilitates the synthesis of functionalized tetralones under mild conditions, significantly enhancing the synthetic application of pyridinium-masked enols.
Authors
- Guohua Liu (ORCID: https://orcid.org/0000-0001-8407-3095)
- Yuhui Hua (ORCID: https://orcid.org/0000-0001-8420-9204)
- Jianfeng Wu (ORCID: https://orcid.org/0000-0003-4444-2639)
- Shisong Lv
- Lingling Li (ORCID: https://orcid.org/0000-0003-3742-8548)
- Rui Liu (ORCID: https://orcid.org/0000-0002-7916-3675)
- Jin Li (ORCID: https://orcid.org/0000-0001-8155-5603)
- Junqiang Wang (ORCID: https://orcid.org/0000-0002-8066-6237)
Institutions
- Shanghai Jiao Tong University (CN)
- Shanghai Normal University (CN)
Publication Details
- Journal
- Organic Letters
- Published
- 2025-06-29
- DOI
- https://doi.org/10.1021/acs.orglett.5c02037
- Citations
- 3
- Primary Topic
- Radical Photochemical Reactions
- Type
- article
- Field-Weighted Citation Impact
- 2.81
Funders
- National Natural Science Foundation of China
- Shanghai Key Laboratory of Rare Earth Functional Materials