Two compounds, the (Z)- and (E)-isomers of 2,4-dibromo-1-p-tolyl-1-butene 2a and 3a, respectively, were isolated in 65% total yield when 1-(1-bromo-1-p-tolylmethyl)cyclopropyl bromide (1a) was heated at 150 degrees C for 1 h. 1,1-Dibromo-2-p-tolylcyclobutane (4a), previously reported to be the only product in this reaction, was not detected. The phenyl analogue of 1a reacted similarly and gave the (Z)- and (E)-isomers of 2,4-dibromo-1-phenyl-1-butene 2b and 3b, respectively, in 60% yield. A rationale for the reaction is presented.

中文翻译：

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1-（1-芳基-1-溴甲基）环丙基溴的热解：重新研究。

当1-（1-溴）分离时，两种化合物分别为2,4-二溴-1-对甲苯基-1-丁烯2a和3a的（Z）-和（E）-异构体，总收率为65％将-1-对甲苯基甲基）环丙基溴（1a）在150℃下加热1小时。未检测到先前报道为该反应的唯一产物的1,1-二溴-2-对甲苯基环丁烷（4a）。1a的苯基类似物反应相似，以60％的收率得到2,4-二溴-1-苯基-1-丁烯2b和3b的（Z）-和（E）-异构体。给出了反应的原理。