14490-17-6

The presence of oviposition-stimulating phytochemicals in hexane extracts of whole leaves of wild tomato (Lycopersicon hirsutum) accession LA 1777 was indicated by oviposition preference assays with gravid female Heliothis zea (Boddie) moths.Three sesquiterpenes isolated from these extracts were identified as (+)-(E)-α-santalen-12-oic acid (1a), (+)-(E)-endo-β-bergamoten-12-oic acid (2a), and (-)-(E)-endo-α-bergamoten-12-oic acid (3a).Structure assignments based primarily on 1H and 13C NMR spectral interpretations were confirmed by conversion to the parent sesquiterpene hydrocarbons and subsequent comparisons with authentic endo-β-bergamotene and/or literature data.The identity of 1a was verified by comparison of its methyl ester (1b) with a sample synthesized from (+)-α-santalol (9).Quantitative assays demonstrated that the two major sesquiterpene acids, 1a and 2a, are the principal oviposition stimulants in the tomato leaf extracts and that the activity of 2a is about twice that of 1a.

Reaction of alkyllithiums 1 with isoprene epoxide 2 gives β,γ-disubstituted allylic alcohols 3 of Z-configuration.The reaction of ?-lithiotricyclene as alkyllithium gives α-santalol 5, which is one of the main constituents in East Indian sandalwood oil.

The lithium-free modification of the Wittig reaction of unstabilized ylides and acyclic α-alkoxy ketones leads to protected trisubstituted allylic alcohols with high stereoselectivity for the Z isomer.