A Convenient Synthesis of Ethyl 3-(2,2-Dihaloethenyl)-2,2-dimethylcyclopropanecarboxylates and Its Modifications for cis-Isomer Enrichment
作者:Kiyohide Matsui、Akira Negishi、Yuriko Takahatake、Kikuo Sugimoto、Tamotsu Fujimoto、Toshiyuki Takashima、Kiyosi Kondo
DOI:10.1246/bcsj.59.221
日期:1986.1
selective transformation of ethyl 4-bromo-6,6,6-trichloro-3,3-dimethylhexanoate to ethyl 6,6,6-trichloro-3,3-dimethyl-4-hexenoate (8a) with piperidine followed by the selective conversion of 8a to cis-2,2-dichloroethenyl compound (cis-5a). Second one is based on the stereoselective cyclization of ethyl 4,6,6,6-tetrachloro-3,3-dimethylhexanoate (t-BuONa/solvent/HMPA) to ethyl cis-2,2-dimethyl-3-(2,2,2
标题化合物 5 的合成涉及 3-methyl-2-buten-1-ol 和原乙酸三乙酯反应生成 3,3-二甲基-4-戊烯酸乙酯,然后将各种四卤化碳加入到双键。所得加合物与碱的反应以高产率提供5。顺式异构体的立体选择性制备通过以下两种方法实现:第一种方法是将 4-溴-6,6,6-三氯-3,3-二甲基己酸乙酯选择性转化为 6,6,6-三氯-3 ,3-二甲基-4-己烯酸酯 (8a) 与哌啶,然后将 8a 选择性转化为顺式 2,2-二氯乙烯基化合物 (顺式 5a)。第二种是基于 4,6,6,6-四氯-3,3-二甲基己酸乙酯(t-BuONa/溶剂/HMPA)立体选择性环化为顺式-2,2-二甲基-3-(2,2 ,