The Absolute Configuration of the Ant Alarm Pheromone Manicone

Abstract

stretching vibration, in accord with a one-minimum poten-The present discussion is relevant not only in the context of the geometrical structure of benzene, it has even more general implications in connection with questions as to the CC bond length alternation and double bond localization (and the related aromaticity problems), respectively, in annulenes of arbitrary ring size, bridged annulenes, and polycyclic x systems with condensed rings. In particular, this holds for analyses of such problems by means of routine X-ray diffraction studies: Caution is obviously called for!13. 161

Synthetic Applications of the Baylis–Hillman Reaction: Simple and Convenient Synthesis of Five Important Insect Pheromones

“…A number of methods have been developed for the stereoselective synthesis of trisubstituted alkenes [2 -6]. As a part of our research program on the synthetic application of the Baylis-Hillman reactions [7 -9], we herein report the simple and convenient synthesis of five important insect pheromones, i.e., of (2E,4S)-2,4-dimethylhex-2-enoic acid (1), a caste-specific substance present in the mandibular glands of the male carpenter ants in the genus Camponotus [10], of (+)-(S)-manicone (2) and (+)-(S)-normanicone (3), the mandibular-gland alarm pheromone components of the ants in the genus Manica [11] [12], and of (+)-(1S)-1-methylbutyl (2E)-2-methylpent-2-enoate (= dominicalure-I; 6) and (+)-(1S)-1-methylbutyl (2E)-2,4-dimethylpent-2-enoate (= dominicalure-II; 7), the aggregation pheromones of the lesser grain borer Rhyzopertha dominica (F) [13].…”