Approach to the synthesis of ethyl(2E,4E)-3,7,11 trimethyl-2,4-dodecadienoate

Abstract

A useful insecticide(la) was synthesized in the following manner. The Knoevenagel condensation of readily available dihydrocitrollenal 3 with 2,2,2-trichloroethyl acetoacetate generated alkylideneacetoacetate 11, which was then treated with zinc-acetic acid to produce 6,10-dimethyl-2-undecanone 10. The addition of the ketone 10 with ethyl 2-phenylsulfinylacetate gave 3-hydroxy-2-sulfinylated ester 9, which was then subjected to dehydration and thermal rearrangement followed by double bond formation to give the desired ester la in respectable yield.