Visible-Light-Induced Synthesis of 1,2,3,4-Tetrahydroquinolines through Formal [4+2] Cycloaddition of Acyclic α,β-Unsaturated Amides and Imides with N,N-Dialkylanilines |
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| Authors: | Prof?Dr Kennosuke Itoh Shun-ichi Nagao Prof?Dr Ken Tokunaga Dr Shigeto Hirayama Dr Fumika Karaki Dr Takaaki Mizuguchi Dr Kenichiro Nagai Noriko Sato Dr Mitsuaki Suzuki Prof?Dr Masashi Hashimoto Prof?Dr Hideaki Fujii |
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| Institution: | 1. Laboratory of Medicinal Chemistry, School of Pharmacy, Kitasato University, Tokyo, 108-8641 Japan;2. Division of Liberal Arts, Center for Promotion of Higher Education, Kogakuin University, Tokyo, 192-0015 Japan;3. Medicinal Research Laboratories, School of Pharmacy, Kitasato University, Tokyo, 108-8641 Japan;4. Department of Chemistry, Faculty of Science, Josai University, Saitama, 350-0295 Japan |
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| Abstract: | 1,2,3,4-Tetrahydroquinolines should be applicable to the development of new pharmaceutical agents. A facile synthesis of 1,2,3,4-tetrahydroquinolines that is achieved by a photoinduced formal 4+2] cycloaddition reaction of acyclic α,β-unsaturated amides and imides with N,N-dialkylanilines under visible-light irradiation, in which a new IrIII complex photosensitizer, a thiourea, and an oxidant act cooperatively in promoting the reaction, is reported. The photoreaction enables the synthesis of a wide variety of 1,2,3,4-tetrahydroquinolines, while controlling the trans/cis diastereoselectivity (>99:1) and constructing contiguous stereogenic centers. A chemoselective cleavage of an acyclic imide auxiliary is demonstrated. |
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| Keywords: | aromatic substitution conjugate addition nitrogen heterocycles photochemistry radical reactions |
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