作者:Makoto Fujita、Kiyosi Kondo、Tamejiro Hiyama
DOI:10.1246/bcsj.60.4385
日期:1987.12
Practical and stereocontrolled approaches to polyfluorinated synthetic pyrethroids based on aldehyde addition of CF3CCl2ZnCl are described. The zinc reagent was allowed to react with 3-formyl-2,2-dimethylcyclopropanecarboxylates (6) to give the corresponding adducts. These were acetylated and then reduced again with zinc to afford (1R*, 3S*)-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-2,2-dimethylcyclopropanecarboxylates (12). The (1R*, 3R*)-isomer was derived from 2,2-dichloro-1,1,1-trifluoro-5-methyl-4-hexen-3-ol by diazoacetylation, Cu(II)-catalyzed intramolecular carbene addition, and finally by the zinc reduction. An alternative access to 12 and its halogen homologues of the (Z)-pyrethroids involves addition of 1-halo-2,2-difluoroethenyl group across the CHO group of 6 and subsequent regio- and stereoselective halogenation.
本文介绍了基于 CF3CCl2ZnCl 的醛加成法制备多氟合成拟除虫菊酯的实用立体控制方法。锌试剂可与 3-甲酰基-2,2-二甲基环丙烷羧酸盐 (6) 反应,生成相应的加合物。这些加合物经乙酰化后再次用锌还原,得到 (1R*,3S*)-3-(2-氯-3,3,3-三氟-1-丙烯基)-2,2-二甲基环丙烷羧酸盐 (12)。(1R*, 3R*)异构体是由 2,2-二氯-1,1,1-三氟-5-甲基-4-己烯-3-醇通过重氮乙酰化、Cu(II)催化的分子内碳烯加成,最后通过锌还原得到的。获得 12 及其 (Z)- 吡咯烷卤素同系物的另一种方法是在 6 的 CHO 基上添加 1-卤代-2,2-二氟乙烯基,然后进行区域和立体选择性卤化。