Reductive cross-coupling of 3-substituted delta 3-cephems with alkenyl halides in an Al/PbBr2/NiBr2(bpy) triplemetal redox system. Synthesis of 3-alkenyl-delta 3-cephems. |
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| Authors: | H Tanaka J Zhao H Kumase |
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| Affiliation: | Department of Applied Chemistry, Faculty of Engineering, Okayama University, Tsushima-naka 3-1-1, Okayama 700-8530, Japan. tanaka95@cc.okayama-u.ac.jp |
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| Abstract: | Synthesis of 3-alkenyl-delta 3-cephems was performed successfully by cross-coupling 3-(trifluoromethylsulfonyloxy or chloro)-delta 3-cephem with alkenyl halides, e.g., vinyl bromide, trans-1-bromo-1-propene, and trans-beta-bromostyrene in an Al/cat.PbBr2/cat.NiBr2(bpy)/NMP (or DMF) system. Reduction of 3-(trifluoromethylsulfonyloxy)-delta 3-cephem into norcephalosporin was also achieved by a similar reaction in the presence of 5 molar equiv of water. Scope and a plausible mechanism of the Al/Pb/Ni triplemetal-redox promoted reactions are discussed. |
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