2-((Z)-((Z)-2-(bromomethylene)cyclopentylidene)methyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane | 1246770-20-6

• 分子结构分类: 有机化合物 - 有机酸及其衍生物 - 硼酸衍生物
• 英文名称: 2-((Z)-((Z)-2-(bromomethylene)cyclopentylidene)methyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
• CAS: 1246770-20-6
• 化学式: C₁₃H₂₀BBrO₂
• 分子量: 299.016
• InChiKey: NTPCDYOREJEYJH-WGEIWTTOSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  4.01
• 重原子数：
  17.0
• 可旋转键数：
  1.0
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.69
• 拓扑面积：
  18.46
• 氢给体数：
  0.0
• 氢受体数：
  2.0

反应信息

• 作为产物：
  描述：

  频哪醇 、 1,6-庚二炔 在 1,3-dimethyl-1,3,2λ²-diazaborolidine,trimethyltin 、 bis-triphenylphosphine-palladium(II) chloride 、 N-溴代丁二酰亚胺(NBS) 、 对甲苯磺酸 作用下， 以 苯 、 氯仿 为溶剂， 反应 18.0h， 以80%的产率得到2-((Z)-((Z)-2-(bromomethylene)cyclopentylidene)methyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane
  参考文献：
  名称：

  Stereoselective Cyclization of Functionalized 1,n-Diynes Mediated by [X−Y] Reagents [X−Y = R₃Si−SnR′₃ or (R₂N)₂B−SnR′₃]: Synthesis and Properties of Atropisomeric 1,3-Dienes

  摘要：

  The borylstannane [-N(Me)CH2CH2(Me)N-]B-SnMe3 is a superior reagent capable of effecting bisfunctionalization-cyclization in several highly functionalized 1,n-diynes, 1,n-enynes, and 1,n-allenynes (including 1,2-dipropargylbenzenes, 2,2'-dipropargylbiphenyls, 4,5-dipropargyldioxolanes, and 1,4-dipropargyl-beta -lactams) where the more well-known silylstannanes fail. Variable-temperature NMR studies showed that conformational restraints imposed by selected backbones increase the activation barrier for the helical isomerization in (Z,2)-dienes that are generated in the cyclization of the diynes. In the biphenyl and dioxolane systems, the reactions proceed with surprisingly good regio- and stereoselectivity. The resulting diazaborolidine derivatives are hydrolytically unstable but can be isolated by recrystallization or precipitation. For further synthetic applications, it is advantageous to convert these compounds in situ into the corresponding dioxaborolidines with either retention of the Me3Sn group or replacement of this group via halodestannylation. The configurations of the vinyl moieties are preserved in these reactions. Highly functionalized dibenzocyclooctadienes, which adorn the carbon frames of several important cytotoxic natural products, can be synthesized using this chemistry.

  DOI：

  10.1021/ja105939v