摘要
本文首次报道用丙二酸二乙酯的相转移催化烃化产物经拆分并分别还原,氧化制得的光活性2-甲-戊烯-4-醛与一系列季鏻盐的Wittig反应。通过此反应共合成新的带有两个双键的光活性昆虫性信息素类似物20个,相应的外消旋物10个。该反应原料易得,反应条件温和,产率高,可作为这类化合物的通用方法。
A series of new optically active insect pheromone analogues containing two double bondswere synthesized smoothly via the Wittig reaction of 2-methylpent-4-en-al and phosphoniumsalts. In order to develop new pest-control methods, study on the correlation between stereo-chemistry and bioactivity becomes a very interesting research recently. The previous effortswere more heavily on the relationship between bioactivity and configuration or position ofvarious functional groups including carbon-carbon double bond individually. However, thestructural influence on bioactivity, when two or more variables applied to the same moleculehas received little attention. In the course of this general project research we developed anovel synthetic route to a series of new optically active insect pheromons analogues with aterminal double bond and a chiral center which is adjacent to another double bond. Thegeneral skeleton is as follows: The key step for this synthetic method is the Wittig reaction of phos-phonium salts with R-or S-2-methylpent-4-en-al which was derived fromthe resolution of the corresponding acid, 1, followed by reduction andoxidation. Neither of these two processes disturbs the chiral center andthe resulting aldehyde has the same configuration with the carboxylic acid, i. e. R-acidyields R-aldehyde and S- acid gives S-aldehyde. The starting material, 2-methyl-pentenyl-4-acid, was obtained easily by alkylation ofdiethyl malonate in phase transfer catalytic condition using polyethylene glycol(PEG) ascatalyst. Phosphonium salts were prepared by the reaction of triphenyl phosphine and ω-bromoal-kanols which were derived from the reaction of hydrobromic acid with corresponding diols.ω-Bromoundecanol was obtained by the esterification of ω-bromoundecanoic acid followed byreduction. We got twenty optically active compounds and their racemates. Their bioactivities arebeing investigated. Compounds with the same molecular formulas, either(S)-or(R)-configu-ration, have the same ~1H NMR, IR and MS spectra. All the reactions described above pro-ceeded smoothiy under mild conditions with satisfactory yields and most of the reagents arecommercially available. So this process may provide a versatile route to the synthesis of thefollowing type compounds which are expected to be candidates for insect pheromone analo-gues by changing R^1, R^2 and R^3. Wittig reaction of 5 and 6, synthesis of (S)-ll-Methyl-9, 13-tetradecadien-l-ol n-Butyl lithium 28 mL(0.885 mol)ether solution was added dropwise with stirring to 9-hyd-roxynonyl triphenyl phosphonium bromide 5.4g (0.011 mol) in THF (60 mL) under nitrogen.After 30 min. 51.1g, (0.011 mol) in THF (10 mL) was added, stirred for 2.5 h and treated withwater (50 mL). The organic layer was seperated and aqueous layer was extracted with ether(4×30 mL). The combined extracts was concentrated and the residue was washed with petro-leum ether (3×40 mL). The extract was concentrated and 7 was obtained by colum chroma-tography (2.24g, 91%). V_(max): 335(OH), 3071(CH=), 1635(C=C), 1055(C—O), 721(CH=CH) cm^(-1). δ_H: 5.6～5.9(1H, m, CH), 4.9～5.4(4H, m, CH_2=, CH=CH), 3.7(2H, t,CH_2O), 2.5(1H, m,≡CH), 1.9～2.4(5 H, m, 2CH_2, OH), 1.2～1.9(12H, m, 6CH_2),0.9～1.1(3H, d, CH_3).
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
1990年第3期230-232,共3页
Chinese Journal of Organic Chemistry
基金
The project is supported by National Natural Selerce Foundation of China
