Synthesis of the algicidal allelochemical from Lemna trisulca(duckweed)

Abstract

Synthesis [in (±)-form] of the allelochemical produced by duckweed, which inhibits algae growth, is reported, Michael addition of nitromethane to 2-methylcyclopent-2-enone followed by carbonyl protection and Nef reaction gives an aldehyde which is elaborated by Wittig reaction and reduction. The cyclopentenone double bond is introduced by selenation methods. A chiral side-chain intermediate is prepared from D-mannitol but its application in the Wittig reaction has not been successful. Comment is made on possible biogenetic routes from a methylene interrupted C₁₆-triene fatty acid.