Kinetics and Stereochemistry of Alkaline Cleavage of 1,1-Diacetyl-2-arylcyclopropane
作者:Osamu Itoh、Nobuyuki Yamamoto、Katsuyuki Nakano、Toshio Sugita、Katsuhiko Ichikawa
DOI:10.1246/bcsj.48.3698
日期:1975.12
The kinetics and the stereochemistry of alkaline cleavage of several 1,1-diacetyl-2-arylcyclopropanes (1) in ethanol-water mixture are reported. The rates can be expressed approximately by a third order equation, rate=k2[1][OH−]2. With para-substituted derivatives (p-CH3, H, p-Cl and p-Br) of 2-phenyl ring, the reaction constant ρ was obtained as +4.3 by plotting logk2 against normal Hammett σ. At
报道了几种 1,1-二乙酰-2-芳基环丙烷 (1) 在乙醇-水混合物中碱性裂解的动力学和立体化学。速率可以近似地由三阶方程表示,速率=k2[1][OH-]2。对于 2-苯环的对位取代衍生物(p-CH3、H、p-Cl 和 p-Br),通过将 logk2 与正常哈米特 σ 作图,反应常数 ρ 为 +4.3。在 0 °C 时,主要产物是热力学不稳定的顺式-1-乙酰基-2-芳基环丙烷。产物中顺反比随反应温度升高而降低。已经讨论了与不可烯醇化的无环 β-二酮的裂解反应有关的反应机理。