Pure (7E,9Z-7, 9-dodecadien-1-yl acetate (1), the sex pheromone of
Lobesiabotrana, has been prepared in 21.6% overall yield by a reaction scheme involving; (i) the cross-coupling of (
E) - 8 - (2 - tetrahydropyranyloxy) -1 - octenyldisiamylborane with 1 - bromo - 1 - butyne, in the presence of a Pd (O) catalyst and base; (ii) the acetylation of the crude product of this reaction; (iii) the (
Z)-stereoselective reduction of the obtained conjugated (
E)-enyn-1-yl acetate. (
E)-9,11-Dodecadien-1-yl acetate (2), a sex pheromone component of
Diparopsiscastanea, has been analogously obtained (in 54.3% overall yield) by cross-coupling of (
E) - 10 - (2 - tetrahydropyranyloxy) - 1 - decenyl borane with vinyl bromide, in the presence of a Pd (O) catalyst and base, followed by acetylation of the crude product. Compound 2, which was 87.7% chemically pure, was purified by column chromatography over SiO
2-AgNO
3. Chemically pure (9
Z, 11
E) - 9,11 - tetradecadien - 1 - yl acetate (3), a sex pheromone component of
Spodopteralittoralis, has been prepared (in 30.2% overall yield) by reaction of 10 - (2 - tetrahydropyranyloxy) - 1 - decynylamagnesium bromide with (
E)-1-iodo-1-butene, in the presence of a Pd (O) catalyst, followed by acetylation of the crude product and by (
Z)-stereoselective reduction of the obtained (
E)-enyn-1-yl acetate.The stereoisomeric purity of 1, 2 and 3 has been evaluated by glc analysis on glass capillary columns or by reverse phase hplc analysis.
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