Cyclopentanoids from cyclopentadiene: synthesis of (-)-methyl jasmonate and (+)-12-oxophytodienoic acid.

Linoleic acid metabolites, (-)-methyl jasmonate and (+)-12-oxophytodienoic acid ((+)-12-oxo-PDA), were prepared from the same precursor (1,2-trans, 1,3-cis, 2'Z)-2-(pent-2'-enyl)-cyclopent-4-en-1,3-diol, which was obtained by regioselective pent-2-enylation of cyclopentadiene and following photooxidation to cis-1,3-diol. A methoxycarbonylmethyl substituent was introduced to the cyclopentane ring via alkylation of the pi-allyl palladium intermediate derived from (1R,2S,3S,2'Z)-3-acetoxy-2-(pent-2'-enyl)cyclopent-4-ene-1-ol with dimethyl malonate for (-)-methyl jasmonate. The alpha-chain was introduced to the cyclopentane ring via the S(N)2 type nucleophilic substitution of (1S,2R,3R,2'Z)-3-acetoxy-2-(pent-2'-enyl)cyclopent-4-ene-1-ol with a dialkylcuprate for (+)-12-oxo-PDA.

Potato tuber cell expansion-inducing activity of stereochemically restricted JA analogs.

Stereochemically restricted analogues of C-7 substituted 7-epi-jasmonate, together with 12-hydroxy jasmonic acid, 12-hydroxy jasmonic acid glucoside, and jasmonic acid conjugated with L-isoleucine (JA-Ile), were synthesized and then tested for potato tuber cell expansion-inducing activity. JA-Ile showed almost the same activity as JA, while the C-7 substituted 7-epi-jasmonates exhibited weaker activity than JA and showed an antagonist effect against JA.