Spirocyclopropane Isoxazolidines, Octahydropyrindin-4-ones and β-Lactams with Biomimetic Ethylene Release from the Electrophilic Substitution of a 1,1-Ethyleneallylzinc Complex
作者:Valentina Paschetta、Franca Cordero、Renée Paugam、Jean Ollivier、Alberto Brandi、Jacques Salaün
DOI:10.1055/s-2001-16057
日期:——
Electrophilic substitution of 1-ethenylcyclopropyl mesylate by 3,3-diethoxypropanal in the presence of palladium(0) (5%) and diethylzinc (2 equivalents) provided 5-cyclopropylidene-1,1-diethoxy-3-hydroxypentane; its nitrone derivatives underwent intramolecular cycloaddition to provide spirocyclopropane isoxazolidines, which then were transformed under thermal or acidic conditions, into octahydropyrindin-4-ones or bicyclic β-lactams with the ethylene phytohormone extrusion, respectively. Use of chiral auxiliaries, i.e. (l)-2-acetoxylactate can lead to enantiomerically enriched heterocycles.
在钯(0)(5%)和二乙基锌(2当量)的存在下,1-乙烯基环丙基甲磺酸酯的亲电取代反应与3,3-二乙氧基丙醛反应,生成了5-环丙叉基-1,1-二乙氧基-3-羟基戊烷;其氮氧自由基衍生物经历分子内环加成反应,生成了螺环丙烷异噁唑啉,随后在热或酸性条件下转化为八氢吡啶-4-酮或双环β-内酰胺,同时脱去乙烯植物激素。使用手性辅助剂,即(l)-2-乙酰氧基乳酸,可以导致手性富集的杂环化合物。