Jasmone precursor synthesis

Farmer EE, Ryan CA, Octadecanoid precursors of jasmonic acid activate the synthesis of wound-inducible proteinase inhibitors, Plant G //4 129—134,1992. 

Inspired by Nature, hydroxocobalamine 247 (X=OH) itself or modified vitamin B12 derivatives (review [331]) were probed as catalysts for radical cyclizations. This methodology is mediated by light and electrochemical or chemical reduction to close the catalytic cycle. It was applied to total syntheses of forskolin 280 by Pattenden [325] (Fig. 67, entry 13) as well as of jasmonate 284 and prostaglandin precursors 287 by Scheffold (entry 14) [326, 327], Starting materials were bromoacetaldehyde cyclohexenyl or cyclopentenyl acetals 278, 281, or 285, which cyclized in the presence of 247 to annulated butyrolactols 279, 283, or 287. In the forskolin synthesis the cyclized radical was reduced directly, while a radical addition ensued in the presence of acetoxyacrylonitrile 282 or ynone 286 in... 

This reaction is important in a synthesis of the perfumery compound ds-jasmone. The alkyne is the precursor to ds-j asm one s alkene side chain. 

Generation of the endocyclic double bond of cyclopentanoids has been accomplished frequently by rDA reaction of the appropriate cyclopentadiene. FVP has been used as the last step of the synthesis of the antibiotic ( )-pentenomycin (53) in 50% yield. " Other cyclopentanoid natural products that are synthesized by procedures based upon a nearly quantitative rDA reaction are jasmone (54) and alkyne (55), a precursor to methyl jasmonate. This same procedure has been applied to the synthesis of intermediates of prostaglandins such as (56). ... 

The a-sulfenyl group can be replaced by a benzothiazolthio group, as demonstrated in the synthesis of the 1,4-diketone (CXXXIV), a precursor of cw-jasmone [Eq. (65)] [10]. The geminal dicarboxylic acid (CXXXVI) can also be transformed into the 1,4-diketone (CXXXIV) by electrochemical decarboxylation as in Eq. (66) [6], suggesting that the substituted malonic acid group is synthetically equivalent to a carbonyl group. 

Numerous synthetic applications of the inteimolecular Pauson-Khand reaction have been reported. Pauson has reported a number of very direct tqrplications of cycloadditions of ethylene in the synthesis of prostanoids and jasmone analogs (e.g. equations 15 and 16). - This is a reliable entry to 2-sub-stituted cyclopentenones. The suitability of cyclopentene and dihydrofuran as substrates has permitted the extension of this work to the preparation of still further varieties of prostaglandin analogs (e.g. equations 27 and 51). Simple 4,5-disubstituted 2-cyclopentenones are not as directly accessible, but may be prepared from the cycloaddition products of norbomadiene (equation 45). A sequence of conjugate addition followed by retro-Diels-Alder reaction affords the product (Scheme 5). Dihydrofuran cycloadditions have been used by Billington in the syntheses of the antibiotic methylenomycin B (Scheme 6), as well as cyclomethylenomycin A (synthetic precursor to the antibiotic methylenomycin A), cyclosarko-mycin (precursor to the antitumor agent sarkomycin) ° and the iridoid Jq>anese hop ether. ... 

The 1,4-dione (66) is a useful precursor for the synthesis of jasmone (67), and several new routes to the dione have been published during the period covered by this Report.Dehydrojasmone (69), which is also an important intermediate in a number of syntheses of jasmone, has been produced from the vinyl allene (68)... 

Moreover, y-diketones are easily transformed into cyclopenteno-nes by base-catalyzed, intramolecular aldolization and subsequent dehydration. The reaction sequences represented by equations (20-24) indicate the utility of the method for the synthesis of dihydrojasmones and jasmone (fragrance), a prostaglandin intermediate, an acoranic sesquiterpene precursor, a-cuprarenone and 3-vetivone [66]. 

When methyl jasmonate was applied to the surface of tomato plants, the synthesis of a defensive proteinase inhibitor protein was induced, not only in the plant to which the application was made but also in nearby plants. In subsequent studies, this compound was shown to have a similar effect with plants of other families as well (Farmer and Ryan, 1990 Pearce et al., 1991). In a series of experiments, it was demonstrated that methyl jasmonate can be a component of interplant communication systems. Octadecanoid precursors of jasmonic acid were able to activate the synthesis of wound-inducible proteinase inhibitors (Crombie and Mistry, 1991 Farmer and Ryan, 1992). Jasmonic acid is a signal transducer in elicitor-induced plant cultures of Rauvolfia canescens and Eschscholtzia californica. Tissue cultures of 36 species of plants could be induced to accumulate second-... 

Among the above-mentioned changes, application of exogenous methyl jasmonate has been shown to stimulate ethylene formation [15-17], carotene synthesis [18] and chlorophyll degradation [15,18] in tomato and/or apple fruits. In ripening tomato fruits, methyl jasmonate also increased the level of the precursor free 18 3 as well as aromatic compounds [19]. Methyl jasmonate is reported to have... 

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