title: Acid-promoted rearrangement of drimane type epoxy compounds and their application in natural product synthesis.
abstract: The reactions of (±)-α-epoxy drimenol (4) and (±)-α-epoxy drimenyl cyanide (6) with acids (proton acid or Lewis acid) selectively gave the rearranged aldehyde (±)-13 and (±)-15 having the hydroindane skeleton, respectively, while the reactions of (±)-4 and (±)-6 with Dibal-H selectively afforded the allyl alcohol (±)-14 and (±)-16, respectively. The reactions of (8aR)-6 and (8aS)-6 with Dibal-H were applied for the determination of the absolute structure of natural 7β-acetoxy-ent-labda-8(17),13(14)E-dien-15-ol (18). The reaction of (±)-α-epoxy bicyclofarnesol (5) and (8aS)-5 with proton acid selectively provided the rearranged ketol (±)- and (8aS)-31 having the hydroindane skeleton, respectively. The optically active (8aS)-31 was converted to the natural (9S)-austrodoric acid (33).
authors.affiliation: School of Pharmaceutical Sciences, Toho University; 2–2–1 Miyama, Funabashi, Chiba, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Fujiwara
authors.forename: Masako
authors.initials: M
authors.lastname: Kinoshita
authors.forename: Akira
authors.initials: A
authors.lastname: Uchida
authors.forename: Machiko
authors.initials: M
authors.lastname: Ono
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kato
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Akita
mesh_terms: D000143:Acids / Q000737:chemistry*; D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D004852:Epoxy Compounds / Q000737:chemistry*; D008968:Molecular Conformation; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D000143:Acids; D001688:Biological Products; D004852:Epoxy Compounds; D000081223:Polycyclic Sesquiterpenes; D012717:Sesquiterpenes; C437376:drimane