(3R*,4R*,5R*)-1,3,4,5-Tetrabromocyclohexene

• 分子结构分类: 有机化合物 - 有机卤素化合物 - 乙烯基卤化物
• 英文名称: (3R*,4R*,5R*)-1,3,4,5-Tetrabromocyclohexene
• 英文别名: (3R,4R,5R)-1,3,4,5-tetrabromocyclohexene
• 化学式: C₆H₆Br₄
• 分子量: 397.73
• InChiKey: RAHFZLFMMSRMEX-PBXRRBTRSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.8
• 重原子数：
  10
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.67
• 拓扑面积：
  0
• 氢给体数：
  0
• 氢受体数：
  0

反应信息

• 作为产物：
  描述：

  3,6-二溴环己烯 在 N-溴代丁二酰亚胺(NBS) 作用下， 以 四氯化碳 为溶剂， 反应 1.0h， 生成 1r,2t,3c,4t,5t-Pentabromocyclohexane 、 (3R*,4R*,5R*)-1,3,4,5-Tetrabromocyclohexene 、 (3R*,4R*,6S*)-1,3,4,6-Tetrabromocyclohexene 、 (3R*,4S*,6S*)-1,3,4,6-Tetrabromocyclohexene
  参考文献：
  名称：

  Radical Bromination of Cyclohexene in CCl4 by Bromine: Addition versus Substitution

  摘要：

  The radical reaction of bromine (10(-2)-10(-5) M)with cyclohexene in CCl4 in the light has been investigated. The reactions have been found to be highly reversible and controlled by both thermodynamics and the availability of Br-2 and HBr as equilibrating agents. The selectivity of substitution over addition is controlled by [Br-2]. Bromine addition to the double bond and allylic substitution occur at comparable rates at room temperature. The limiting substitution/addition ratio was found to be 4.0 +/- 0.2 for [Br-2] less than 10(-3) M. While the beta-bromocyclohexyl radical is generated very rapidly, its steady-state concentration is kept low by its rapid reversion to cyclohexene. Substitution via the allyl radical, while relatively slow, is irreversible and fast enough to maintain the concentration of bromine at sufficiently low level to prevent significant addition. The equilibrium constant for the reaction 1 + Br reversible arrow 2a is estimated to be 500 M(-1), and the rate constant for substitution k(2s) as 2000 M(-1) s(-1). The ratio of removal of hydrogen from cyclohexene, 3-bromocyclohexene, and 3,6-dibromocyclohexene by bromine radical was found to be 2.2:1.0:0.1. The ratio for addition of bromine to the double bond was 5.5:1.0:<0.1. A series of polybromo derivatives have been obtained and characterized by NMR spectroscopy as stable intermediates in the exhaustive bromination of cyclohexene. m-Dibromobenzene is the major aromatic product.

  DOI：

  10.1021/jo00095a029

文献信息

• Radical Bromination of Cyclohexene in CCl4 by Bromine: Addition versus Substitution
  作者：D. W. McMillen、John B. Grutzner

  DOI：10.1021/jo00095a029

  日期：1994.8

  The radical reaction of bromine (10(-2)-10(-5) M)with cyclohexene in CCl4 in the light has been investigated. The reactions have been found to be highly reversible and controlled by both thermodynamics and the availability of Br-2 and HBr as equilibrating agents. The selectivity of substitution over addition is controlled by [Br-2]. Bromine addition to the double bond and allylic substitution occur at comparable rates at room temperature. The limiting substitution/addition ratio was found to be 4.0 +/- 0.2 for [Br-2] less than 10(-3) M. While the beta-bromocyclohexyl radical is generated very rapidly, its steady-state concentration is kept low by its rapid reversion to cyclohexene. Substitution via the allyl radical, while relatively slow, is irreversible and fast enough to maintain the concentration of bromine at sufficiently low level to prevent significant addition. The equilibrium constant for the reaction 1 + Br reversible arrow 2a is estimated to be 500 M(-1), and the rate constant for substitution k(2s) as 2000 M(-1) s(-1). The ratio of removal of hydrogen from cyclohexene, 3-bromocyclohexene, and 3,6-dibromocyclohexene by bromine radical was found to be 2.2:1.0:0.1. The ratio for addition of bromine to the double bond was 5.5:1.0:<0.1. A series of polybromo derivatives have been obtained and characterized by NMR spectroscopy as stable intermediates in the exhaustive bromination of cyclohexene. m-Dibromobenzene is the major aromatic product.