N-Heterocyclic Carbene-Catalyzed Asymmetric Synthesis of Cyclopentenones
Zhizhou Chen, Xiangwen Kong, Shengtong Niu, Shuang Yang*, Jinggong Liu*, Bolai Chen*, Benlong Luo, Changyu Zhou, Chenglin Ding and Xinqiang Fang*
*UCAS, Fuzhou 350100; Guangdong Provincial Hospital of TCM, Guangzhou 510120, China,
Email: yangshuang
fjirsm.ac.cn, liujinggong001163.com,
chenbolai337163.com, xqfangfjirsm.ac.cn
Z. Chen, X. Kong, S. Niu, S. Yang, J. Liu, B. Chen, B. Luo, B. Luo, C. Zhou, C. Ding, X. Fang, Org. Lett., 2021, 23, 3403-3408.
DOI: 10.1021/acs.orglett.1c00870
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Abstract
A N-heterocyclic carbene-catalyzed reaction of enals with α-diketones enables an asymmetric construction of cyclopentenones in a highly diastereo- and enantioselective manner. The protocol tolerates substrates with both aromatic and aliphatic groups.
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Typical procedure for the annulation reaction
Under argon atmosphere, diketone (1.2 mmol) was added in one portion to a stirred solution of enal (1 mmol), K2CO3 (27.6 mg, 0.2 mmol), DPQ (535.0 mg, 1.3 mmol) and catalyst (83.8 mg, 0.2 mmol) in THF (5.0 mL). The reaction system was stirred at room temperature for 6 h. Then the mixture was filtered through a celite pad, and the filtrate was concentrated to give crude product. The crude product was purified by flash chromatography using petroleum ether-ethyl acetate (20:1 v/v) as eluent.
Key Words
ID: J54-Y2021
