PROCESSES FOR PREPARING 2-ISOPROPENYL-5-METHYL-4-HEXENOIC ACID, 2-ISOPROPENYL-5-METHYL-4-HEXEN-1-OL, AND A CARBOXYLATE ESTER THEREOF
申请人:Shin-Etsu Chemical Co., Ltd.
公开号:US20210323902A1
公开(公告)日:2021-10-21
The present invention provides a process for preparing 2-isopropenyl-5-methyl-4-hexenoic acid of the following formula (4), comprising steps of:
subjecting a Grignard reagent of the following general formula (1), wherein R
1
represents a linear, branched, or aromatic monovalent hydrocarbon group having 1 to 8 carbon atoms, and X represents a chlorine atom, a bromine atom, or an iodine atom, and 1,1,1,3,3,3-hexamethyldisilazane to a deprotonation reaction to form a 1,1,1,3,3,3-hexamethyldisilazane derivative; and subjecting 2-methyl-3-buten-2-yl 3-methyl-2-butenoate of the following formula (3) to a rearrangement reaction in the presence of the 1, 1, 1,3,3,3-hexamethyldisilazane derivative to form 2-isopropenyl-5-methyl-4-hexenoic acid (4).
本发明提供了一种制备如下式(4)所示的2-异丙烯基-5-甲基-4-己烯酸的方法,包括以下步骤:将如下一般式(1)的格氏试剂进行去质子化反应,其中R1代表具有1至8个碳原子的直链、支链或芳香族单价碳氢基团,X代表氯原子、溴原子或碘原子,以及1,1,1,3,3,3-六甲基二硅氮烷,形成1,1,1,3,3,3-六甲基二硅氮烷衍生物;并在1,1,1,3,3,3-六甲基二硅氮烷衍生物存在下,将如下式(3)的2-甲基-3-丁烯-2-基-3-甲基-2-丁烯酸酯进行重排反应,形成2-异丙烯基-5-甲基-4-己烯酸(4)。