Synthetic applications of the Baylis-Hillman reaction: Simple and convenient synthesis of five important insect pheromones

A simple and convenient synthesis of five important insect pheromones by means of Baylis-Hillman adducts is described, i.e., of (2E,4S)-2,4-dimethylhex-2-enoic acid (1), a mandibular-gland secretion of the male carpenter ant in the genus Camponotus, of (+)-(S)-manicone (2) and (+)-(S)-normanicone (3), two mandibular-gland constituents of Manica ants, and of (+)-dominicalure-I (6) and (+)-dominicalure-II (7), two aggregation pheromones of the lesser grain borer Rhyzopertha dominica (F). For the first time, the potential of the Baylis-Hillman chemistry for the stereoselective synthesis of trisubstituted olefins was successfully applied to the synthesis of these pheromone compounds.