2-(2,6-dimethylbenzylidene)-1,1,3,3-tetramethylcyclopentane | 1595253-61-4

• 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: 2-(2,6-dimethylbenzylidene)-1,1,3,3-tetramethylcyclopentane
• 英文别名: 1,3-Dimethyl-2-[(2,2,5,5-tetramethylcyclopentylidene)methyl]benzene；1,3-dimethyl-2-[(2,2,5,5-tetramethylcyclopentylidene)methyl]benzene
• CAS: 1595253-61-4
• 化学式: C₁₈H₂₆
• 分子量: 242.404
• InChiKey: GHFSROITHSOKAM-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  6
• 重原子数：
  18
• 可旋转键数：
  1
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.56
• 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：

  2-(α-lithio-o,o'-dimethylbenzylidene)-1,1,3,3-tetramethylcyclopentane 以 四氢呋喃 、 环戊烷 、 氘代苯 为溶剂， 反应 0.01h， 生成 2-(2,6-dimethylbenzylidene)-1,1,3,3-tetramethylcyclopentane
  参考文献：
  名称：

  Microsolvation, aggregation, and pseudomonomolecular, ionic sp2-stereoinversion mechanism of two exocyclic β,β-di-tert-alkyl-α-arylvinyllithiums

  摘要：

  A THF-solvated, crystalline, exocyclic alkenyllithium, (tert-alkyl)(2)C=C(Li) ePh, was synthesized and shown to be a disolvated dimer in the solid state and in toluene as the solvent; increasing amounts of the monomeric species emerged on cooling the toluene solution. In THF as the solvent, only the trisolvated monomer was present and identified as a contact ion pair (CIP) through its scalar C-13,Li-6 NMR coupling. This ground-state needs only one further THF ligand as a catalyst for breaking the C-Li bond with formation of a tetrasolvated, solvent-separated ion pair (SSIP) on the way to the transition state of cis/trans sp2-stereoinversion. The ensuing pseudomonomolecular, ionic mechanism is confirmed by low pseudoactivation parameters: enthalpy Delta H psi double dagger = 6.9(3) kcal mol(-1); entropy Delta H-psi(double dagger) = 23.3(9) cal mol(-1) K-1. Similar parameters were found with 2,6-dimethylphenyl in place of Ph. (C) 2014 Elsevier B. V. All rights reserved.

  DOI：

  10.1016/j.jorganchem.2014.05.031

文献信息

• Ring expansion and vinylic nucleophilic substitution competing for (tert-alkyl)2CC(Li)–Cl in carbenoid chain processes
  作者：Rudolf Knorr、Thomas Menke、Karsten-Olaf Hennig、Johannes Freudenreich、Petra Böhrer、Bernhard Schubert

  DOI：10.1016/j.tet.2014.03.004

  日期：2014.4

  (tert-alkyl)2CC(Li)–Cl as transient intermediates. The chains are longer and the overall reactions much slower in tert-butyl methyl ether (t-BuOMe) than in THF as the solvent. In competition with the fast SNV step of these Cl,Li-carbenoids, the Fritsch–Buttenberg–Wiechell (FBW) ring expansion in t-BuOMe (but less so in THF) generates short-lived cyclohexyne species, which are trapped by the accompanying

  乙烯基亲核取代（S Ñ V）未活化的，环状的α的反应，α-dichloroalkenes [（叔烷基）2 ç的CCl 2 ]与芳基锂（RLi的），得到（叔烷基）2 Ç C（Cl）的-R是被认为是类胡萝卜素链反应，涉及不饱和Cl，Li-类胡萝卜素（叔烷基）2 C C（Li）–Cl作为过渡中间体。与作为溶剂的THF相比，叔丁基甲基醚（t -BuOMe）中的链更长，总反应慢得多。与快速的S N竞争这些Cl，Li类胡萝卜素的V阶跃，在t -BuOMe中的Fritsch–Buttenberg–Wiechell（FBW）环膨胀（但在THF中则较少）产生了短寿命的环己炔物种，这些环己炔物种被伴随的RLi物种捕获以产生氯环己烯衍生物[（叔烷基）–（Cl）C C（R）–（叔烷基）]作为FBW链产物。