关键词: 立体选择合成, 性信息素, 有机硼烷, (Z)-、(E)-7-链烯-1-醇乙酸酯

Abstract: The hydroborating agnet, monobromoborane-dimethyl sulfide(H₂BBr · SMe₂) 2b, was prepared from the reaction of borane-dimethyl sulfide(H₃B · SMe₂) with carbon tetrabromide in the molar ratio 1 : 1 at 60℃ for 20 h. Some insect sex pheromones with Z- and E-7-alken-l-yl acetate have been prepared by Zweifel's cis- and trans-olefine synthesis. Monohaloborane-dimethyl sulfide(H₂BX · SMe₂,X = Cl,Br) 2 hydroborates terminal alkenes rapidly and quantitatively to give dialkylhalobo-ranes 3 at room temperature. Dialkylboranes 4, prepared in situ via reduction of 3 with LiAlH₄, hy-droborate 2-(7-octyn-l-yloxy-)tetrahydropryan 5 and 2-(8-bromo-7-octyl-1-yloxy-)tetrahydropy-ran 6 to provide B-(trans-1-alkenyl)dialkylboranes 7 and B-(cis-1-bromo-1-alkenyl)dialkylboranes 10 respectively. Treatment of 7 with iodine in the sodium methoxide at -78℃ forms the corresponding cis-disubstituted alkenes 8, followed by the acetylation to give Z-7-alken-1-yl acetates 9. Treatment of 10 with sodium methoxide at 0℃ provides B- (trans-1-alkyl-1-alkenyDalkylborinate esters 11, which on protonalysis produce the E-7-alken-l-yl acetate 12, followed by the usual way to provide E-7-alken-1-ols 13.

Key words: Stereoselective synthesis, Sex pheromones, Organoboranes, Z-, E-7-alken-1-yl acetate