- The role of germacrene D as a precursor in sesquiterpene biosynthesis: Investigations of acid catalyzed, photochemically and thermally induced rearrangements
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Germacrene D is considered as a precursor of many sesquiterpene hydrocarbons. We have investigated the acid catalyzed as well as the photochemically and thermally induced rearrangement processes of germacrene D isolated from several Solidago species, which contain both enantiomers of germacrene D. Enantiomeric mixtures of sesquiterpenes of the cadinane, eudesmane (selinane), oppositane, axane, isodaucane, and bourbonane group as well as isogermacrene D were identified as main products and made available as reference compounds for structure investigations and stereochemical assignments of plant constituents. δ-Amorphene, one of the rearrangement products, was identified as a natural product for the first time. The absolute configuration of γ-amorphene was revised by correlation with the absolute configuration of germacrene D. The mechanisms of the rearrangement reactions are discussed. (C) 2000 Elsevier Science Ltd.
- Buelow, Nils,Koenig, Wilfried A
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p. 141 - 168
(2007/10/03)
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- Stereoselective Reactions. XVI. Total Synthesis of (-)-β-Bourbonene by Employing Asymmetric (2+2) Photocycloaddition Reaction of Chiral Butenolide
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Total synthesis of (-)-β-bourbonene (3) was achieved by employing the (2+2) photocycloaddition reaction of (S)-γ-pivaloyloxymethyl-β-methyl-γ-butenolide (5e) with cyclopentenone ethyleneacetal (15).The major photoadduct (16) was readily converted to the c
- Tomioka, Kiyoshi,Tanaka, Masahide,Koga, Kenji
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p. 1201 - 1207
(2007/10/02)
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- CONFORMATIONAL CONTROL OF ENOLATE GEOMETRY: A SHORT SYNTHESIS OF GERMACRENE-D
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A synthesis of (+/-)-germacrene-D is reported that employs a site- and stereoselective enolization of a conformationally biased ten-membered ring ketone.
- Schreiber, Stuart L.,Hawley, Ronald C.
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p. 5971 - 5974
(2007/10/02)
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- AN ASYMMETRIC SYNTHESIS OF CIS, ANTI, CIS-TRICYCLO2,6>DECANES APPLYING γ-HYDROXYMETHYL-γ-BUTYROLACTONE AS A CHIRAL SYNTHON. FIRST ASYMMETRIC TOTAL SYNTHESIS OF (-)-β-BOURBONENE
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The asymmetric total synthesis of cis, anti, cis-tricyclo2,6>decane sesquiterpene β-bourbonene is described.The key (2+2) photocycloaddition was carried out applying the optically pure butenolide derivative 6b as a chiral synthon.
- Tomioka, Kiyoshi,Tanaka, Masahide,Koga, Kenji
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p. 3401 - 3404
(2007/10/02)
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