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:EP3901125A1
公开(公告)日:2021-10-27
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 R1 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下式(4)的 2-异丙烯基-5-甲基-4-己烯酸的工艺,包括以下步骤:
将通式(1)的格氏试剂(其中 R1 代表具有 1 至 8 个碳原子的线性、支链或芳香族单价烃基,X 代表氯原子、溴原子或碘原子)和 1,1,1,3,3,3-六甲基二硅氮烷进行去质子化反应,生成 1,1,1,3,3,3-六甲基二硅氮烷衍生物;并使下式(3)的 2-甲基-3-丁烯-2-基 3-甲基-2-丁烯酸酯在 1,1,1,3,3,3-六甲基二硅氮烷衍生物存在下进行重排反应,生成 2-异丙烯基-5-甲基-4-己烯酸(4)。