INSECT PHEROMONES AND THEIR ANALOGUES. XVI. PRACTICAL SYNTHESIS OF HEXADEC-9Z-ENAL - A COMPONENT OF THE SEX PHEROMONE OF THE COTTON BOLLWORM Heliothis armigera

Article abstract of DOI:10.1007/BF00598768

A synthesis of hexadec-9Z-enal - a component of the sex pheromone of the cotton bollworm Heliothis armigera (Huebner) - based on cyclooctene (I) is proposed.Through a solution of 22 g of (I), 250 ml of cyclohexane, and 40 ml of MeOH is passed (at 5 deg C) 0.2 M O3/O2, the solution is decanted off, and the precipitated ozonide is dissolved in 200 ml of MeOH and is reduced with 19 g of NaBH4 (40 deg C) with the isolation, after the usual working up, of 23.4 g of octane-1,8-diol (II).From 0.5 mole of (II) and 0.6 mole of 45percent HBr 8-bromooctan-1-ol (III) is obtained and this is converted into 1-(2-(THPL)oxy)-8-bromooctane (IV).The condensation of (IV) with oct-1-yne (Ar, LiNH2, HMPTA, 10 deg C, 1 h, and then 55 deg C, 10 h) leads to 1-(2-THPL-oxy)hexadec-9-yne (V) the hydrolysis of which (MeOH, H2O, p-TsOH, 20 deg C for 20 h) yields hexadec-9-yn-ol (VI).The reduction of (VI) (Et2O, iso-BuMgBr, Cp2TiCl2, 0 deg C, 15 min, then 20 deg C, 1 h) yields hexadec-9Z-en-1-ol (VII).The oxidation of (VII) (PyHCrO3⁺ Cl^-, CH2Cl2, 20 deg C, 2 h) gives hexadec-9Z-enal (VIII).Characteristics of the compounds (yield (percent), n_D²⁰⁽²⁵⁾: (II) - 80, mp 61-62 deg C; (III) - 75, 1.4807; (IV) - 99, -; (V) - 52, 1,4650; (VI) - 85, 1.4657; (VII) - 99, 1.4650; (VIII) - 98, 1.4600.Characteristics of the IR and PMR spectra of compounds (V-VII) are given.