title: Asymmetric Total Synthesis of ent-Pyripyropene A.
abstract: An asymmetric total synthesis of ent-pyripyropene A was achieved by a convergent synthetic route. We used our originally developed Ti(III) -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.
authors.affiliation: Department of Applied Chemistry, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan). sfuse@res.titech.ac.jp.|Present address: Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama, 226-8503 (Japan). sfuse@res.titech.ac.jp.
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Fuse
authors.affiliation: Department of Applied Chemistry, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan).
authors.forename: Ayako
authors.initials: A
authors.lastname: Ikebe
authors.affiliation: Department of Applied Chemistry, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan).
authors.forename: Kazuya
authors.initials: K
authors.lastname: Oosumi
authors.affiliation: Department of Applied Chemistry, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan).
authors.forename: Tomoya
authors.initials: T
authors.lastname: Karasawa
authors.affiliation: Department of Applied Chemistry, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan).
authors.forename: Keisuke
authors.initials: K
authors.lastname: Matsumura
authors.affiliation: Japan Biological Informatics Consortium (JBIC), 2-4-7, Aomi, Koto-ku, Tokyo 135-0064 (Japan).
authors.forename: Miho
authors.initials: M
authors.lastname: Izumikawa
authors.affiliation: Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan).
authors.forename: Kohei
authors.initials: K
authors.lastname: Johmoto
authors.affiliation: Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro-ku, Tokyo 152-8552 (Japan).
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Uekusa
authors.affiliation: National Institute of Advanced Industrial Science and Technology (AIST), 2-4-7, Koto-ku, Tokyo 135-0064 (Japan).
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shin-ya
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3, Aza-Aoba, Aramaki, Aoba, Sendai 980-8578 (Japan).
authors.forename: Takayuki
authors.initials: T
authors.lastname: Doi
authors.affiliation: Yokohama College of Pharmacy, 601, Matano-cho, Totsuka-ku, Yokohama-shi, Kanagawa 245-0066 (Japan).
authors.forename: Takashi
authors.initials: T
authors.lastname: Takahashi
mesh_terms: D002384:Catalysis; D015394:Molecular Structure; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry; D012717:Sesquiterpenes / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D014025:Titanium / Q000737:chemistry
chemical_list: D011725:Pyridines; D012717:Sesquiterpenes; C082792:pyripyropene A; D014025:Titanium
keywords: insecticidal activity; meroterpenoids; natural products; radical reactions; titanium