The four 14C-labelled stereoisomers of both 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid and 3-(2,2-dibromoethenyl)-2,2-dimethylcyclopropanecarboxylic acid, the improtant acid components of various potent insecticidal pyrethroids, were prepared efficiently from [1-14C]chrysanthemic acid (5) for use in comparative metabolic studies. α-Bromo-β-naphthyl d,l-cis, trans-[1-14C]chrysanthemate (6) was oxidized with osmium tetroxide-sodium periodate to give the formyl ester (7) in 78% yield. Wittig reaction of 7 with dichloromethylenetris(dimethylamino)phosphorane at −75 - −70 °C afforded the dichlorovinylated ester (8) quantitatively. Optical resolution of 8 by preparative HPLC using a chiral-phase column led to the four stereoisomers (8a - 8d) with optical purities more than 99%. Hydrolyses of the esters (8a - 8d) yielded the corresponding optically active 3-(2,2-dichloroethenyl)-2,2-dimethyl [1-14C]cyclopropanecarboxylic acids (1a - 1d) quantitatively. Similarly, Wittig reaction of the formyl ester (7) with dibromomethylenetris(dimethylamino)phosphorane, followed by optical resolution and hydrolysis, gave four optically active 3-(2,2-dibromoethenyl)-2,2-dimethyl [1-14C]cyclopropanecarboxylic acids (2a - 2d) in considerably high yields.

中文翻译：

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14C 标记的 3-(2,2-二氯乙烯基)-和 3-(2,2-二溴乙烯基)-2,2-二甲基环丙烷羧酸的所有立体异构体的制备

3-(2,2-二氯乙烯)-2,2-二甲基环丙烷甲酸和 3-(2,2-二溴乙烯)-2,2-二甲基环丙烷甲酸的四种 14C 标记立体异构体，各种强效杀虫剂的重要酸组分拟除虫菊酯是由 [1-14C] 菊酸 (5) 有效制备的，用于比较代谢研究。α-溴-β-萘基 d,l-cis, trans-[1-14C] 菊酸酯 (6) 用四氧化锇-高碘酸钠氧化得到甲酰酯 (7)，产率为 78%。7 与二氯亚甲基三（二甲氨基）正膦在 -75 - -70 °C 下的 Wittig 反应定量提供了二氯乙烯基酯（8）。使用手性相柱通过制备型 HPLC 对 8 进行光学拆分，得到光学纯度超过 99% 的四种立体异构体 (8a - 8d)。酯 (8a - 8d) 的水解定量产生相应的旋光 3-(2,2-二氯乙烯基)-2,2-二甲基 [1-14C] 环丙烷羧酸 (1a - 1d)。类似地，甲酰酯 (7) 与二溴亚甲基三（二甲氨基）正膦发生 Wittig 反应，然后进行旋光拆分和水解，得到四种旋光 3-（2,2-二溴乙烯基）-2,2-二甲基 [1-14C] 环丙烷羧酸酸 (2a - 2d) 的产量相当高。