由有机硼烷立体选择合成(Z)、(E)链烯-1-醇乙酸酯类昆虫性信息素

The stereoselective Synthesis of Insect Sex Pheromone of Z- and E-Alken-1-yl Acetates via Organoboranes

等摩尔的甲硼烷甲硫醚(H_3B·SMe_2)与四溴化碳在60℃下反应20h,定量得到一溴硼烷甲硫醚。从链端烯烃、一卤硼烷甲硫醚和2-[7-辛炔-1-氧基]四氢吡喃及其8-溴代衍生物出发,经硼氢化反应和Zweifel的顺-,反-烯烃合成法,立体选择地合成了鳞翅目昆虫性信息素:(Z)-7-十四烯-1-醇乙酸酯9a、(Z)-7-十六烯-1-醇乙酸酯9b、(E)-7-十四烯-1-醇乙酸酯12及其相应的醇13。产物经GC分析和MS、~1H及^(13)C NMR数据证实了它们的纯度和几何构型。

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.