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Asymmetric Total Synthesis of ent‐Pyripyropene A |
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| Authors: | Dr. Shinichiro Fuse Ayako Ikebe Kazuya Oosumi Tomoya Karasawa Keisuke Matsumura Dr. Miho Izumikawa Dr. Kohei Johmoto Dr. Hidehiro Uekusa Dr. Kazuo Shin‐ya Prof. Takayuki Doi Prof. Takashi Takahashi |
| Affiliation: | 1. Department of Applied Chemistry, Tokyo Institute of Technology, 2‐12‐1, Ookayama, Meguro‐ku, Tokyo 152‐8552 (Japan);2. Present address: Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta‐cho, Midori‐ku, Yokohama, 226‐8503 (Japan);3. Japan Biological Informatics Consortium (JBIC), 2‐4‐7, Aomi, Koto‐ku, Tokyo 135‐0064 (Japan);4. Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2‐12‐1, Ookayama, Meguro‐ku, Tokyo 152‐8552 (Japan);5. National Institute of Advanced Industrial Science and Technology (AIST), 2‐4‐7, Koto‐ku, Tokyo 135‐0064 (Japan);6. Graduate School of Pharmaceutical Sciences, Tohoku University, 6‐3, Aza‐Aoba, Aramaki, Aoba, Sendai 980‐8578 (Japan);7. Yokohama College of Pharmacy, 601, Matano‐cho, Totsuka‐ku, Yokohama‐shi, Kanagawa 245‐0066 (Japan) |
| Abstract: | An asymmetric total synthesis of ent‐pyripyropene A was achieved by a convergent synthetic route. We used our originally developed TiIII‐catalyzed radical cyclization to construct an AB‐ring portion that consisted of a trans‐decalin skeleton with five contiguous stereogenic centers. The coupling between the AB‐ring and the DE‐ring portions, and a subsequent C‐ring cyclization, led to the total synthesis of ent‐pyripyropene A. An evaluation of the insecticidal activity of ent‐pyripyropene A against two aphid species revealed that ent‐pyripyropene A was 35–175 times less active than naturally occurring pyripyropene A. This result indicated that the biological target of pyripyropene A recognizes the absolute configuration of pyripyropene A. |
| Keywords: | insecticidal activity meroterpenoids natural products radical reactions titanium |