title: Synthetic studies toward penitrem E: enantiocontrolled construction of B-E rings.
abstract: Enantiocontrolled construction of B-E rings of penitrem E was accomplished from 4-iodoindole in 13 steps with an overall yield of 1.7%. Diastereoselective Tf2NH-catalyzed (2+2)-cycloaddition between silyl enol ether and methyl acrylate furnished a tetracyclic product possessing the characteristic cyclobutane ring bearing a hydroxyl group.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba 6-3, Aramaki, Aoba-ku, Sendai 980-8578, Japan. tokuyama@mail.pharm.tohoku.ac.jp.
authors.forename: Yu
authors.initials: Y
authors.lastname: Yoshii
authors.forename: Takanori
authors.initials: T
authors.lastname: Otsu
authors.forename: Norihiko
authors.initials: N
authors.lastname: Hosokawa
authors.forename: Kiyosei
authors.initials: K
authors.lastname: Takasu
authors.forename: Kentaro
authors.initials: K
authors.lastname: Okano
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Tokuyama
mesh_terms: D060326:Chemistry Techniques, Synthetic; D018360:Crystallography, X-Ray; D015394:Molecular Structure; D009183:Mycotoxins / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D009183:Mycotoxins; C003626:tremortin