New Synthesis of (11Z,13Z)-11,13-Hexadecadienal, the Female Sex Pheromone of the Navel Orangeworm

Facile and Efficient Syntheses of (11Z,13Z)-Hexadecadienal and Its Derivatives: Key Sex Pheromone and Attractant Components of Notodontidae

“…Alkynes alkylation is widely used in the synthesis of terminal alkynes and alkynols [22,25,26,27], especially sex pheromones of insect pests [28,29,30]. At the condition of −40 °C under argon, alkylation of lithium propargyl alcohol (C3 synthon) with 1,1-diethoxy-10-iododecane ( 5 ) in tetrahydrofuran/hexamethyl phosphoryl triamide furnished the acetylenic compound.…”

“…However, the reduction gave additional products generated via the 1,4-reduction of the en-yne. As previously reported, 3–4 equivalents of alkylborane in THF are necessary to effectively complete hydroboration of the triple bond [14,22]. The reaction system was treated with acetic acid to achieve protonolysis.…”

“…The structures of (11 Z ,13 Z )-hexadecadienal ( 1 ), (11 Z ,13 Z )-hexadecadienol ( 2 ), and (11 Z ,13 Z )-hexadecadien-1-yl acetate ( 3 ) contain a conjugated ( Z , Z )-diene moiety. The construction of the ( Z , Z )-conjugated diene system has been achieved in the past using a series of schemes: (1) the Wittig reaction: addition reaction of aldehyde with a Z type-unsaturated enol [13]; (2) Cadiot–Chodkiewicz coupling coupled with hydroboration-protonolysis of 1,3-diyne [14]; (3) diimide reduction of acetylene and palladium-catalyzed coupling [15]; and (4) catalytic coupling of metal catalysts and hydroboration-protonolysis [16,17,18,19,20,21,22].…”

“…Highly selective methods have to be employed for constructing the ( Z , Z )-conjugated diene system and conjugated en-yne moiety of a Z configuration, which exist in the structure of (11 Z ,13 Z )-hexadecadienal ( 1 ) and ( Z )-13-hexadecen-11-ynal ( 4 ), respectively. Furthermore, both (11 Z ,13 Z )-hexadecadienal ( 1 ) and ( Z )-13-hexadecen-11-ynal ( 4 ) possess the labile terminal formyl group, therefore the timing of placing the terminal formyl group is also important, owing to the fact that oxidation in the final step may isomerize the ( Z , Z )-conjugated diene system [22]. The formyl group is introduced into its intermediate as acetal derivatives in an earlier stage of synthesis, which has been shown to avoid isomerization of the ( Z , Z )-conjugated diene system from oxidation [17,18,19,20].…”

Identification and Field Evaluation of Sex Pheromone Components of the Pear Barkminer Moth, Spulerina astaurota

“…A coupling reaction of 2 with lithium trimethylsilylacetylide in a mixed solvent of THF and HMPA and desilylation of the product with potassium carbonate in methanol produced a THP ether of 9-decyn-1-ol (3). Sonogashira-Hagihara coupling (Sonogashira et al, 1975) between 3 and (Z)-1-bromo-1-butene, which was prepared from (E)-2-pentenoic acid (Mori and Brevet, 1991;Mori, 2009), furnished a THP ether of (Z)-11-tetradecen-9-yn-1-ol (4). 1 H NMR analysis of 4 confirmed the Z configuration of the double bond at the 11-position; i.e., olefinic proton resonating at δ 5.40 and 5.80 ppm showed a similar coupling constant (J=10.5 Hz) as that usually detected for (Z)-isomers of disubstituted alkenes.…”