90673-89-5Relevant academic research and scientific papers
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.
