Concise Preparation of the (3E,5Z)-Alkadienyl System. New Approach to the Synthesis of Principal Insect Sex Pheromone Constituents

• Published in: Journal of agricultural and food chemistry 2004-08, Vol.52 (16), p.5047-5051
• Main Authors: Ragoussis, Valentine, Panopoulou, Maria, Ragoussis, Nikitas
• Format: Article
• Language: English
• Subjects: Alkadienes - chemistry; Animals; Biological and medical sciences; chemical reactions; Control; Fundamental and applied biological sciences. Psychology; Gas Chromatography-Mass Spectrometry; Hydrogen Bonding; insect pests; Insecta; Insecta - chemistry; Integrated pest control; Magnetic Resonance Spectroscopy; Molecular Structure; Phytopathology. Animal pests. Plant and forest protection; plant pests; Protozoa. Invertebrates; Sex Attractants - chemical synthesis; sex pheromones; synthesis
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf049406b

A new rapid and low-cost preparation of the (3E,5Z)-3,5-alkadienyl system, encountered in several insect pheromone constituents, was developed. Knoevenagel condensation of (E)-2-alkenals with ethyl hydrogen malonate in dimethyl sulfoxide, in the presence of a catalytic amount of piperidinium acetate, led to a mixture of geometrical isomers of ethyl 3,5-alkadienoates and ethyl 2,4-alkadienoates, from which the (3E,5Z)-3,5-alkadienoate was conveniently separated, by the use of urea inclusion complex formation. The importance of this procedure has been illustrated by the preparation of the (3E,5Z)-3,5-tetradecadienoic acid (megatomoic acid) 1, the (3E,5Z)-3,5-dodecadienyl acetate 2, and the (3E,5Z)-3,5-tetradecadienyl acetate 3. These compounds are the main components of insect sex pheromones and constitute synthetic targets of considerable interest for the semiochemical community. Keywords: Knoevenagel condensation; pheromone synthesis; semiochemicals; megatomoic acid; Attagenus megatoma; Bonagota cranaodes; Recurvaria leucatella