Aromatic Monochlorination Photosensitized by DDQ with Hydrogen Chloride under Visible‐Light Irradiation |
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Authors: | Prof. Dr. Kei Ohkubo Atsushi Fujimoto Prof. Dr. Shunichi Fukuzumi |
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Affiliation: | 1. Department of Material and Life Science, Graduate School of Engineering, Osaka University and ALCA and SENTAN, Japan Science and Technology Agency (JST), Suita, Osaka, Japan;2. Department of Chemistry and Nano Science, Ewha Womans University, Seoul, Korea;3. Faculty of Science and Technology, Meijo University, ALCA and SENTAN, Japan, Science and Technology Agency (JST), Nagoya, Aichi, Japan;4. (+81)?6‐6879‐4732 |
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Abstract: | Photochlorination of aromatic substrates by hydrogen chloride with 2,3‐dichloro‐5,6‐cyano‐p‐benzoquinone (DDQ) occurs efficiently to produce the corresponding monochlorinated products selectively under visible‐light irradiation. The yields for the chlorination of phenol were 70 % and 18 % for p‐ and o‐chlorophenol, respectively, without formation of further chlorinated products. The photoinduced chlorination is initiated by electron transfer from Cl? to the triplet excited state of DDQ. The radical intermediates involved in the photochemical reaction have been detected by time‐resolved transient absorption measurements. |
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Keywords: | chlorination laser flash photolysis photoinduced electron transfer quinone radical |
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