triisopropylsilyl 3,4-dibromopyrrole-2-carboxylate | 130408-99-0

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 吡咯
• 英文名称: triisopropylsilyl 3,4-dibromopyrrole-2-carboxylate
• CAS: 130408-99-0
• 化学式: C₁₄H₂₃Br₂NO₂Si
• 分子量: 425.236
• InChiKey: OHCQXNJNYMETOO-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  5.87
• 重原子数：
  20.0
• 可旋转键数：
  5.0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.64
• 拓扑面积：
  42.09
• 氢给体数：
  1.0
• 氢受体数：
  2.0

反应信息

• 作为产物：
  描述：

  1-(三异丙基甲硅烷基)吡咯 在 N-溴代丁二酰亚胺(NBS) 、 正丁基锂 作用下， 以 四氢呋喃 为溶剂， 反应 1.5h， 生成 triisopropylsilyl 3,4-dibromopyrrole-2-carboxylate
  参考文献：
  名称：

  N-(Triisopropylsilyl)pyrrole. A progenitor "par excellence" of 3-substituted pyrroles

  摘要：

  A very effective strategy has been devised for the synthesis of 3-substituted pyrroles based on the use of the triisopropylsilyl (TIPS) moiety as a sterically demanding nitrogen substituent to obstruct the attack of electrophilic reagents at the alpha-positions. 1-(Triisopropylsilyl)pyrrole (1) undergoes highly preferential kinetic electrophilic substitution at the beta-position with a variety of electrophiles (Br+, I+, NO2+, RCO+, etc.) and fluoride ion induced desilylation of the products provides the corresponding 3-substituted pyrroles in good overall yields. Competitive trifluoroacetylation experiments demonstrate that substitution of TIPS-pyrrole at the alpha-positions is decelerated by a factor of > 10(4), vs pyrrole at the same sites, without affecting reactivity at the beta-positions. 1-(Triisopropylsilyl)-3-bromopyrrole (2) is readily converted into the 3-lithio compound 44 by bromine-lithium interchange with alkyllithium reagents. This previously unavailable, formal equivalent of 3-lithiopyrrole is itself an excellent source of a wide range of beta-substituted pyrroles, many of which would not be directly preparable from 1. TIPS-pyrrole can be 3,4-dihalogenated and these compounds undergo sequential halogen-metal interchange trapping reactions. This process is exemplified by an efficient, three-step synthesis of the antibiotic verrucarin E (63) from the dibromo compound 5.

  DOI：

  10.1021/jo00313a019