Photoredox Cyclization of N-Arylacrylamides for Synthesis of Dihydroquinolinones
Zhaosheng Liu, Shuai Zhong, Xiaochen Ji*, Guo-Jun Deng and Huawen Huang*
*College of Chemistry, Xiangtan University, Xiangtan 411105, China,
Email: xcji
xtu.edu.cn, hwhuangxtu.edu.cn
Z. Liu, S. Zhong, X. Ji, G.-J. Deng, H. Huang, Org. Lett., 2022, 24, 349-353.
DOI: 10.1021/acs.orglett.1c04015
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Abstract
A metal- and additive-free photoredox cyclization of N-arylacrylamides provides dihydroquinolinones in good yields in the presence of the organic light-emitting molecule 4CzIPN as photocatalyst.
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proposed mechanism
4CzIPN
General procedure for photocyclization of acrylamides
A 10 mL reaction vessel was charged with N-methyl-N-phenylcinnamamide (0.2 mmol, 1.0 equiv), 4CzIPN (3.2 mg, 0.004 mmol, 2 mol%), CH3CN (1 mL, 0.2 M). The atmosphere was exchanged by applying vacuum and backfilling with N2 (this process was conducted for three times). The resulting mixture was stirred at 2000 RPM for 48 hours under irradiation with a 35 W blue LED. The crude reaction mixture was quenched with saturated sodium carbonate and extracted with ethyl acetate (3 × 20 mL). The extracts were combined, dried over sodium sulfate, filtered and the volatiles were removed under reduced pressure. Then, column chromatography was performed using silica gel (200-300 mesh) or thin layer chromatography was performed using silica gel (GF254) to give product.
Key Words
dihydroquinolinones, photochemistry, organocatalysis
ID: J54-Y2022
