title: Absolute Configuration of Kelsoene and Prespatane.
abstract: The absolute configurations of the rare sesquiterpenes, kelsoene and prespatane, were determined to be (1S, 2R,5S, 6S, 7R, 8R)-2,8-dimethyl-6-(1-methylethenyl)tricyclo[5.3.0.0(2,5)] decane (IUPAC name) and (1R, 2S, 5R, 6R, 7R, 8S)-1,5-dimethyl-8-(1-methylethenyl) tricyclo-[5.3.0.0(2,6)] decane, respectively, on the basis of the observed chemical shifts and NOEs in NOESY and NOEDS experiments after conversion with the chiral reagent, 2'-methoxy-1,1'-binaphthalene-2-carbohydroximoyl chloride (MBCC). The absolute configurations of kelsoene and prespatane thus determined suggest that initial cyclization of FPP from the si-face at C-10 to form a 10R-germacradienyl cation leads to kelsoene, while that from the re-face leads to prespatane via the 10S-germacradienyl cation.
authors: a Department of Bioresource Science, Obihiro University of Agriculture and Veterinary Medicine.
authors: K
authors: K
authors: Nabeta
authors: M
authors: M
authors: Yamamoto
authors: H
authors: H
authors: Koshino
authors: H
authors: H
authors: Fukui
authors: Y
authors: Y
authors: Fukushi
authors: S
authors: S
authors: Tahara
mesh_terms: D003500:Cyclization; D035926:Hepatophyta / Q000737:chemistry*; D015394:Molecular Structure; D009281:Naphthalenes / Q000737:chemistry; D012717:Sesquiterpenes / Q000737:chemistry* / Q000302:isolation & purification; D045788:Sesquiterpenes, Germacrane / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D009281:Naphthalenes; D012717:Sesquiterpenes; D045788:Sesquiterpenes, Germacrane; C469029:kelsoene
keywords: 2′-methoxy-1,1′-binaphthalene-2-carbohydroximoyl chloride; absolute configuration; chiral reagent; kelsoene; prespatane