Enantioselective Total Synthesis of the Unnatural and the Natural Stereoisomers of Vittatalactone

The striped cucumber beetle, Acalymma vittatum, is a cause of major damage to cucurbit crops in North America. To develop an environmentally benign plant protection strategy, recent research has focused on identifying sex pheromones of the cucumber beetle. In this context, we developed the asymmetric total synthesis of the aggregation pheromone of A. vittatum, Vittatalactone, to determine its absolute configuration and to further examine the pheromone response in field studies. The synthesis features an enzyme-catalyzed approach toward the deoxypropionate structural motif. A preformed organocopper reagent could then be coupled in an enantioselective o-DPPB-directed allylic substitution with a functionalized o-DPPB-ester. By means of this efficient transformation, Vittatalactone could be obtained following a highly convergent synthetic process.