Rhodium‐Catalyzed [3+2+2] and [2+2+2] Cycloadditions of Two Alkynes with Cyclopropylideneacetamides |
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| Authors: | Tomoka Yoshida Yuki Tajima Masayuki Kobayashi Koji Masutomi Prof Dr Keiichi Noguchi Prof Dr Ken Tanaka |
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| Institution: | 1. Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184‐8588 (Japan);2. Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, Ookayama, Meguro‐ku, Tokyo 152‐8550 (Japan) http://www.apc.titech.ac.jp/～ktanaka/;3. Instrumentation Analysis Center, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184‐8588 (Japan);4. Japan Science and Technology Agency (JST), ACT‐C, 4‐1‐8 Honcho, Kawaguchi, Saitama, 332‐0012 (Japan) |
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| Abstract: | It has been established that a cationic rhodium(I)/H8‐binap complex catalyzes the 3+2+2] cycloaddition of 1,6‐diynes with cyclopropylideneacetamides to produce cycloheptadiene derivatives through cleavage of cyclopropane rings. In contrast, a cationic rhodium(I)/(S)‐binap complex catalyzes the enantioselective 2+2+2] cycloaddition of terminal alkynes, acetylenedicarboxylates, and cyclopropylideneacetamides to produce spiro‐cyclohexadiene derivatives which retain the cyclopropane rings. |
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| Keywords: | asymmetric catalysis cycloaddition heterocycles rhodium synthetic methods |
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