α-bromo-2,6-diisopropylstyrene | 156023-28-8

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯和取代衍生物
• 英文名称: α-bromo-2,6-diisopropylstyrene
• CAS: 156023-28-8
• 化学式: C₁₄H₁₉Br
• 分子量: 267.209
• InChiKey: FCWMIXMEPUHVPV-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  5.3
• 重原子数：
  15.0
• 可旋转键数：
  3.0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.43
• 拓扑面积：
  0.0
• 氢给体数：
  0.0
• 氢受体数：
  0.0

反应信息

• 作为反应物：
  描述：

  α-bromo-2,6-diisopropylstyrene 在 正丁基锂 作用下， 以 乙醚 、 环戊烷 为溶剂， 反应 0.25h， 生成 α-(2,6-diisopropylphenyl)vinyllithium
  参考文献：
  名称：

  Microsolvation, Dimerization, and sp²-Stereoinversion of Monomeric α-(2,6-Diisopropylphenyl)vinyllithium

  摘要：

  The title compound is entirely monomeric in THF as the solvent, but its two ortho-diisopropyl substituents (in contrast to two tert-butyl groups) do not suffice to prevent its dimerization in Et2O: At -107 degrees C, the disolvated dimer (43% of the total material in monomeric formula units) was accompanied by the disolvated (15%) and the trisolvated monomers (42%). Increasing temperatures reduced trisolvation by Et2O to disolvation and diminished also the combined monomer portions (10% at +25 degrees C); hence, dimerization in Et2O is endothermic (+3.1 kcal mol(-1)) but favored by a strongly positive entropy. Microsolvation by only one tert-butyl methyl ether (t-BuOMe) ligand per Li cation of the dimer in t-BuOMe solution was discovered through NMR integration; this disolvated dimer was also observed in cyclopentane as the solvent from -85 to at least +25 degrees C (hence, no monomer, no higher aggregate). Aryl rotations about the (partial) single bond to the carbanionic center C-alpha were assessed from the temperatures of NMR signal coalescences of the diastereotopic methyls in an isopropyl group: they are slowest in THF as the solvent because the monomer is then always trisolvated, and delocalization of the negative charge from C-alpha into the aromatic pi-system is therefore most efficient (hence, more rotation-resistant). Microsolvation controls also the cis/trans sp(2)-stereoinversion, which is faster in THF than in the other three solvents because only one additional THF ligand must temporarily be immobilized (performing THF catalysis) on the way to the tetrasolvated, ionic transition state that involves rehybridization (close to sp) of C-alpha (pseudoactivation entropy Delta S-psi double dagger = -23.6 cal mol(-1) K-1). Most of the pertaining microsolvation numbers became available through their empirical relationship with the measured one-bond C-13-Li-6 NMR coupling constants.

  DOI：

  10.1021/om5010995
• 作为产物：
  描述：

  1-(2,6-diisopropylphenyl)ethanol 在 氢氧化钾 、 potassium hydrogensulfate 、 氢溴酸 、 溴 、 sodium amide 、 sodium bromide 作用下， 以 四氢呋喃 、 乙醇 、 氯仿 、 溶剂黄146 、 甲苯 为溶剂， 50.0~180.0 ℃ 、5.33 kPa 条件下， 反应 10.75h， 生成 α-bromo-2,6-diisopropylstyrene
  参考文献：
  名称：

  Knorr, Rudolf; Ruhdorfer, Jakob; Boehrer, Petra, Liebigs Annalen der Chemie, 1994, # 4, p. 433 - 438

  摘要：

  DOI：