Simon Fielder

Actinidia arguta: volatile compounds in fruit and flowers

More than 240 compounds were detected when the volatile components of the flowers and the fruit from several Actinidia arguta genotypes were investigated. Around 60-70 different compounds were extracted from individual tissues of each genotype. Two different methods of volatile sampling (headspace and solvent) favoured different classes of compounds, dependent upon their volatilities and solubilities in the flower or fruit matrices. The compounds extracted from flowers largely comprised linalool derivatives including the lilac aldehydes (12a-d) and alcohols (13a-d), 2,6-dimethyl-6-hydroxyocta-2,7-dienal (8), 8-hydroxylinalool (9), sesquiterpenes, and benzene compounds that are presumed metabolites of phenylalanine and tyrosine. Extracts of fruit samples contained some monoterpenes, but were dominated by esters such as ethyl butanoate, hexanoate, 2-methylbutanoate and 2-methylpropanoate, and by the aldehydes hexanal and hex-E2-enal. A number of unidentified compounds were also detected, including 8 from flowers that are so closely related that they are either isomers of one compound or two or more closely related compounds. This is the first report of the presence of a range of linalool derivatives in Actinidia.

SYNTHESIS OF SESQUITERPENE POLYENE HYDROPEROXIDES BY REGIO- AND STEREOSELECTIVE TRANSPOSITION REACTIONS

Abstract Isomeric unsaturated alcohols (8), (16), (18) and (20), on exposure to hydrogen peroxide or water in the presence of an acid catalyst, undergo exceptionally regio- and stereoselective substitution reactions to form hydroperoxide (3) and alcohol (8) respectively. E Z isomeric ratios of transposition products indicate that the intermediate acyclic carbocations (21) and (22) are not interconverting under the reaction conditions. Practical syntheses of α-farnesene autoxidation products have been developed based on these transposition reactions.