Syntheses of 14C-labelled (+)-trans-chrysanthemum mono- and di-carboxylic acids, and of related compounds

Simple, stereospecific syntheses of 14C-labelled (+)-trans-chrysanthemum mono- and di-carboxylic acids, required for biosynthetic and toxicological work, are described. The methyl esters of the acids are obtained by Wittig condensation between the (+)-trans-cyclopropane aldehyde (2) and the appropriate 14C-labelled phosphoranes. Aldehyde (2) is obtained in high yield by osmium tetroxide–sodium periodate oxidation of methyl trans-chrysanthemate. The conversion of methyl chrysanthemate into chrysanthemum dicarboxylic acid via aldehyde (2) proceeds in an overall yield of 39%.Methyl nor-(9) and bisnor-(8)(±)-trans-chrysanthemates are synthesised from (2) by condensation with appropriate alkylidenephosphoranes.