| 223508-88-1

• CAS: 223508-88-1
• 化学式: C₃₀H₄₈Si₂Th
• 分子量: 696.92
• InChiKey: VMEZASSPHRDISI-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  None
• 重原子数：
  None
• 可旋转键数：
  None
• 环数：
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• sp3杂化的碳原子比例：
  None
• 拓扑面积：
  None
• 氢给体数：
  None
• 氢受体数：
  None

反应信息

• 作为产物：
  描述：

  dimethylbis(η5-pentamethylcyclopentadienyl)thorium 、 三甲基乙炔基硅 以 四氢呋喃 为溶剂， 生成
  参考文献：
  名称：

  Oligomerization and Cross-Oligomerization of Terminal Alkynes Catalyzed by Organoactinide Complexes

  摘要：

  Various organoactinides of the type Cp*(2)An(C=CR)(2) (Cp* = C(5)Me(5); An = Th, U) have been synthesized from the corresponding Cp*(2)AnMe(2) complexes by addition of an equimolar amount or an excess of the corresponding terminal alkyne. Attempts to trap the mono(acetylide) complexes Cp*(2)An(C=CR)(Me) were successful for only the transient species Cp*(2)U(C=C(i-Pr))(Me). The bis(acetylide) complexes are active catalysts for the linear oligomerization of terminal alkynes HC=CR. The regioselectivity and the extent of oligomerization depend strongly on the alkyne substituent R, whereas the catalytic reactivities are similar for both organoactinides. Reaction with tert-butylacetylene regioselectively yields the 2,4-disubstituted 1-butene-3-yne dimer, whereas (trimethylsilyl)acetylene is regioselectively trimerized to (E,E)-1,4,6-tris(trimethylsilyl)-1,3-hexadiene-5-yne, with small amounts (3-5%) of the corresponding 2,4-disubstituted 1-butene-3-yne dimer. Oligomerization with less bulky alkyl- and aryl-substituted alkynes produces a mixture of oligomers. Cross-oligomerizations reactions induce the formation of specific cross dimers and trimers. Mechanistic studies on the selective trimerization of HC=CSiMe(3) show that the first step in the catalytic cycle is the C=C bond insertion of the terminal alkyne into the actinide-acetylide bond. The kinetic rate law is first order in organoactinide and in alkyne, with Delta H(double dagger) = 11.1(3) kcal mol(-1) and Delta S(double dagger) = - 45.2(6) eu. The turnover-limiting step is the release of the organic oligomer from the alkenyl-actinide complex. The latter key organometallic intermediate has been characterized by spectroscopic and poisoning studies. A plausible mechanistic scenario is proposed for the oligomerization of terminal alkynes.

  DOI：

  10.1021/ja9836390