Concise preparation of the (3E,5Z)-alkadienyl system. New approach to the synthesis of principal insect sex pheromone constituents.
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.
Department of Chemistry, Laboratory of Organic Chemistry, University of Athens, Panepistimiopolis Zographou, 157 71 Athens, Greece. ragousi@chem.uoa.gr
Valentine
V
Ragoussis
Maria
M
Panopoulou
Nikitas
N
Ragoussis
D000466:Alkadienes / Q000737:chemistry*; D000818:Animals; D008401:Gas Chromatography-Mass Spectrometry; D006860:Hydrogen Bonding; D007313:Insecta / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D012724:Sex Attractants / Q000138:chemical synthesis*
D000466:Alkadienes; D012724:Sex Attractants