98102-88-6Relevant academic research and scientific papers
A REGIOSPECIFIC DOUBLE BOND SHIF INDUCED BY TITANOCENE CATALYSTS
Turecek, F.,Antropiusova', H.,Mach, K.,Hanus, V.,Sedmera, P.
, p. 637 - 640 (1980)
cis-Bicyclo(4.3.0)-3,7-nonadien is isomerized by titanocene-derived catalysts to bicyclo(4.3.0)-2,9-nonadiene.
Synthesis of 12-Oxophytodienoic Acid (12-OxoPDA) and the Compounds of its Enzymic Degradation Cascade in Plants, OPC-8:0, -6:0, -4:0 and -2:0 (epi-Jasmonic Acid), as their Methyl Esters
Crombie, Leslie,Mistry, Kamlesh M.
, p. 1981 - 1991 (2007/10/02)
The synthesis of 12-Oxophytodienoic acid, and the compounds of its enzymatic degradation sequence, OPC-8:0, -6:0, -4:0 and -2:0, important plant metabolites derived from linolenic acid, is reported.The syntheses use the known cyclopent-3-ene-1,2-diacetic acid as an early intermediate, and this is derived from the Cope rearrangement of 5-vinyltrinorborn-2-ene via bicyclonona-3,7-diene.Iodolactonisation and tributyltin hydride reduction provides the key intermediate (3-oxo-2-oxabicyclooctan-6-yl)acetic acid for the OPC series, whilstphenylselenolactonisation and elimination provides the necessary unsaturated lactone (7-oxo-8-oxabicyclooct-2-en-4-yl)acetic acid for 12-oxoPDA.Members of the OPC-series were made by chain extending the saturated oxabicyclooctane acid: that for the OPC-4:0 involved double Arndt-Eistert reaction, whilst the intermediates for OPC-6:0 and -8:0 were made by Kolbe anodic crossed coupling.The lactones were than converted via their lactols, Wittig reaction, esterfication and oxidation, into the compounds of the OPC ester series, including OPC-2:0 (methyl epi-jasmonate).The unsaturate lactone 8-(7-oxo-8-oxabicyclooct-2-en-4-yl)octanoic acid required for 12-oxoPDA synthesis could also be prepared by anodic synthesis either from (7-oxo-8-oxa-bicyclooct-2-en-4-yl)acetic acid, or from its 2-phenylseleno-2,3-dihydro precursor as elimination occurred concomitantly during the reaction.Since yields were low, the unsaturated acid lactone was converted into its lactol and the (Z)-pent-2-enyl side-chain was inserted first.After TBDMS blocking of the cyclopentene hydroxy group, the side-chain was elaborated to give5-(pent-2-enyl)cyclopent-2-enylacetaldehyde and chain extension carried out by a Grignard-demesylation procedure.Sequential desilylation and depyranylation, followed by oxidation of the diol, gave 12-oxoPDA, isolated as its methyl ester.
Synthesis of compounds of the 12-oxophytodienoic acid cascade: OPCs-8:0, 6:0, 4:0, and 2:0 (epi-jasmonic acid)
Crombie, Leslie,Mistry, Kamlesh M.
, p. 539 - 540 (2007/10/02)
The β-oxidation compounds of the cis series OPC-8:0, 6:0, 4:0, and 2:0 (epi-jasmonic acid), formed metabolically from dihydro-12-oxophytodienoic acid, are synthesised as their methyl esters; plant regulating functions are associated with the acids of this series.
Diademane and Structurally Related Compounds, I. Preparation and Characteristic Reactions of Some Tris-?-homobenzene Hydrocarbons
Kaufmann, Dieter,Fick, Hans-Heinrich,Schallner, Otto,Spielmann, Werner,Meyer, Lueder-Ulrich,et al.
, p. 587 - 609 (2007/10/02)
Diademane (5) and 1,6-Homodiademane (6) are the first hydrocarbons with cis-tris-?-homobenzene skeletons.They were prepared by photoisomerization of the olefinic precursors 8 (snoutene) and 15 (4,5-homosnoutene), respectively.In an analogous reaction the bridged trans-tris-?-homobenzene 7 was formed from 17 (endo,exo-bishomobarrelene). 7 is more easily obtained from 17 by rhodium(I)-catalyzed isomerization or from exo,exo-bishomobarrelene 18 by thermal rearrangement.The unbridged 4 was prepared using a newly developed synthetic sequence starting from 1,3-cyclohexadiene.The thermal rearrangement of 5 and 6 to triquinancene (9) and 1,10-homotriquinancene (16) is very facile; the gas phase kinetic parameters (ln k (5) = 33.7 - 31600/RT and ln k (6) = 32.2 - 28300/RT, both first order) strongly corroborate, that these rearrangements are concerted ?2S + ?2S + ?2S> cycloreversions. -labelled 4 upon thermolysis yields a trans-bicyclonona-3,7-diene (31 22) with a 12C-labelling pattern, which proves its formation via a 3-step mechanism.The first step in this sequence most probably is a ?2S + ?2S + ?2S> cycloreversion with ln k = 30.8 - 42000/RT (first order).Only the bridged compound 7 does not follow the sample path, probably due to excessive ring strain in the transition state, and prefers a stepwise cycloreversion leading to 18 and at least 5 secondary products.
