Spiroacetals and Other Venom Constituents as Potential Wasp Attractants
摘要:
The major volatile spiroacetals from the venom of both the common wasp, Vespula vulgaris and the German wasp V. germanica, viz. 7-methyl-1,6-dioxaspiro[4,5]decane and 7-ethyl-2-methyl-1,6-dioxaspiro[4,5]decane, respectively, were synthesized by known methods. These acetals, along with N-isopentylacetamide (the major volatile amide from wasp venom), 2-heptanone (a honeybee pheromone), 2-methyl-3-buten-2-ol (a component of hornet venom), cuticle wax from V. vulgaris, and venom sacs from both wasp species were assayed by EAG and olfactory bioassay for attractancy to V. vulgaris workers. Antennal responses to all test chemicals were recorded. Acetal isomers (+/-)-2 and (+/-)-3, N-isopentylacetamide, and 2-heptanone were attractive to V. vulgaris workers at levels of <1 mu mol. Greater quantities of the same compounds were repellent to V. vulgaris workers.
Photolysis of diazomethane in (S)-2-methyloxetane gives 2- and 3-methyltetrahydrofuran (1:3.2), the latter being formed with 21 % net retention of configuration. In contrast, rhodium acetate catalysis yields racemic 3-methyltetrahydrofuran exclusively.
Tetraphenylstibonium methoxide (1) is an effective reagent for the synthesis of oxiranes and oxetanes from the corresponding 1,2- and 1,3-halohydrins, respectively. As the reaction conditions are neutral, oxiranes bearing an ester moiety were obtained intact without undergoing solvolysis. In addition, oxetanes, whose preparation was not generally facile, were formed in good yields under mild conditions (60-80°C).
With [RhCl(CO)(2)](2)-amine as catalyst, the reaction of oxetanes with a hydrosilane and carbon monoxide results in ring-opening silylformylation to give gamma-siloxy aldehydes in 42-83% yields. Addition of amines is essential for the silylformylation to proceed, and 1-methylpyrazole is the most effective additive among the amines examined. The ring-opening of 2-alkyloxetanes occurs predominantly at the primary carbon atom with regioselectivity of 95%.
Amouroux, Roger; Jatczak, Maria; Chastrette, Maurice, Bulletin de la Societe Chimique de France, 1987, # 3, p. 505 - 510
作者:Amouroux, Roger、Jatczak, Maria、Chastrette, Maurice