1Department of Biological Organic Chemistry, Institute of Chemical and Environmental Research of Barcelona (CSIC), Jordi Girona 18-26. 08034 - Barcelona, Spain. 2Indian Institute of Chemical Technology, Hyderabad 500007, India.
The sex pheromone of the leopard moth Zeuzera pyrina has been identified as mixture of (E,Z)-2,13-octadecadienyl acetate, (E,Z)-3,13-octadecadienyl acetate and (Z)-13-octadecenyl acetate (Tonini, C.; Cassani, G.; Massardo, P.; Guglielmetti, G.; Castellari, P. L. J. Chem. Ecol. 1986, 12, 1545-1558; Malosse, C.; Descoins, C.; Frérot, B. J. High Res. Chrom. 1993, 16, 123-125). Analysis of the sex pheromone of our strain confirmed the presence of the three components in 86:4:10 ratio, respectively. Although a number of synthesis have been reported, some of them are non-stereoselective, others afford low overall yields for preparative purposes, and, to our knowledge, neither of them is convergent. In this communication we present a new, convergent and highly efficient synthesis of the dienic acetates of the sex pheromone of the leopard moth through sulfones. (E,Z)-2,13-Octadecadienyl acetate was obtained in 26.8% overall yield from 2-chloromethyltetrahydrofuran with a stereochemical purity of 98%Z and ³ 99.5%E of the double bonds at C-13 and C-2, respectively. In turn, (E,Z)-3,13-octadecadienyl acetate was prepared in 13.5% overall yield from the same precursor and with a stereochemical purity >98%E and 94%Z of the double bonds at C-3 and C-13, respectively. The synthetic compounds were electrophysiologically (EAG) active and blends in adequate proportions found to be highly attractive to males in the field.