E)-conjugated dienoates and dienamides of high stereoisomeric purities are prepared via thermal SO2 extrusion from cis-2,5-disubstituted-2,5-dihydrothiofene-1,1-dioxides generated by a retro Diels-Alder reaction. Applications of this method to the syntheses of two insecticidal natural dienamides : pellitorine and pipercide and of methyl tetradeca-2E,4,5-trienoate, an insect sex pheromone, are described.
高热异构体纯度的(E)和(E,E)共轭二烯酸酯和二烯酰胺是通过热SO 2从由逆Diels生成的顺式-2,5-二取代-
2,5-二氢噻吩-1,1-二氧化物热SO 2挤出制备的-Al木反应。描述了该方法在两种杀虫性天然二烯酰胺的合成中的应用:拼花碱和
哌啶和昆虫性信息素
十四烷-2E,4,5-
三烯酸甲酯。