Abstract Males of the giant white butterfly Idea leuconoe release a complex mixture of compounds during courtship. Besides alkaloids, aromatics, terpenoids and hydrocarbons, several lactones have been identified in the pheromone bouquet. Two simple stereoselective methods to create the lactones in good enantiomeric excesses have been developed. The generation of the stereocenters of the β-lactones 1a and 1b is based on a ...