27840-34-2Relevant academic research and scientific papers
The role of germacrene D as a precursor in sesquiterpene biosynthesis: Investigations of acid catalyzed, photochemically and thermally induced rearrangements
Buelow, Nils,Koenig, Wilfried A
, p. 141 - 168 (2007/10/03)
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.
Regioselective intramolecular base-induced synthesis of α,β-unsaturated acyldecalins from decalones via carbon homologation with TosMIC. Synthesis of (±)-6-eudesmen-4α-ol and (±)-vetiselinene
Blay,Schrijvers,Wijnberg,De Groot
, p. 2188 - 2194 (2007/10/02)
Reaction of decalones 6a-e with TosMIC gives adducts 7a-e which can be methylated concomitant with regioselective migration of the double bond to an endocyclic position. The regioselectivity of the double bond migration is determined by the presence or absence of a free hydroxyl group at C(4). Base-catalyzed methylation of TosMIC adducts 7b-d, possessing a free hydroxyl group at C(4), and subsequent acid-catalyzed hydrolysis led preferentially to the C(6)-C(7) double bond isomers 10b-d, respectively. An intramolecular deprotonation of H-6 is considered to be responsible for this regioselectivity. If the hydroxyl group at C(4) is absent or protected as in 7a and 7e, respectively, the C(7)-C(8) double bond isomers 9a and 9c are obtained via an intermolecular abstraction of a sterically less shielded proton at C(8). The usefulness of this methodology is illustrated by the total synthesis of (+)-6-eudesmen-4α-ol (18) and (+)-vetiselinene (22).
Synthesis of Selina-4(14),7(8)-diene, an Antipode of Vetiselinene
Vig, O. P.,Kumar, S. D.,Vig, Rashmi,Sharma, S. D.
, p. 871 - 872 (2007/10/02)
Selina-4(14),7(8)-diene (I) has been synthesised from trans-10β-methyl-8-methylene-2-decalone (II) through a four-step procedure.Formylation of II affords the keto-aldehyde (III), which is converted into isobutyl ether (IV) to protect the aldehyde group in III.The compound (IV) on Grignard reaction with isopropyl iodide and subsequent treatment with 50percent sulphuric acid yields trans-10β-methyl-8-methylene-3-formyl-2-isopropyl-Δ2-octalin (V).Decarbonylation of V using chlorotris(triphenylphosphine)rhodium complex gives the title compound (I).
