Synthesis of Douglas Fir Tussock Moth Sex Pheromone from Cyclic Phosphonium Salt

Abstract

Douglas Fir Tussock Moth (Orgyia pseudotsugata) sex pheromone has been synthesized as an application of tandem Wittig reactions of 1, 1-diphenylphosphorinanium bromide [1].
Methylthio group was introduced into α-position to phosphorus atom of [1]. Subsequent Wittig reaction of the resulting salt with decanal gave vinyl sulfide [4] in 56% yield. The Wittig-Horner reaction of [4 ] with hexanal followed by treatment with sodium hydride gave the diene [6] (21% yield based on [4]) as a precursor of the pheromone. Treatment of [6] with aqueous hydrochloric acid gave the desired pheromone [7] in 82% yield.