Synthesis of δ-lactonic pheromones of Xylocopa hirsutissima and Vespa orientalis and an allomone of some ants of genus Camponotus

Simple preparations of cis-3,6-dimethyltetrahydro-2-pyrone, VII,6-n-undecyltetrahydro-2-pyrone, XVIIb, and 6-n-pentyl-5,6-dihydro-2-pyrone, XVIa, have been achieved. Products VII and XVIIb, respectively, are the major constituent of the pheromonal blend of a carpenter bee (Xylocopa hirsutissima) and the pheromone of the queens of the Oriental hornet (Vespa orientalis). The lactone XVIa is a suspected defensive allomone in two species of formicine ants of the genus Camponotus. All three compounds have been prepared from dehydroacetic acid, I, a cheap and industrially available starting material. © 1983 Plenum Publishing Corporation.