2-bromopenta-1,4-dien-3-ol

• 分子结构分类: 有机化合物 - 有机卤素化合物 - 卤代醇
• 英文名称: 2-bromopenta-1,4-dien-3-ol
• 化学式: C₅H₇BrO
• 分子量: 163.014
• InChiKey: LWWYULYKYIEAOL-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.5
• 重原子数：
  7
• 可旋转键数：
  2
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.2
• 拓扑面积：
  20.2
• 氢给体数：
  1
• 氢受体数：
  1

反应信息

• 作为产物：
  描述：

  溴乙烯 、 丙烯醛 在 正丁基锂 、 lithium bromide 作用下， 以 四氢呋喃 、 乙醚 、 正戊烷 为溶剂， 反应 1.75h， 以74%的产率得到2-bromopenta-1,4-dien-3-ol
  参考文献：
  名称：

  1-Bromo-1-lithioethene:  A Practical Reagent for the Efficient Preparation of 2-Bromo-1-alken-3-ols

  摘要：

  A reliable preparative-scale synthesis of 1-bromo-1-lithioethene is reported. This reagent undergoes clean 1,2-addition with a range of aldehydes and ketones at -105 degreesC to afford the corresponding 2-bromo-1-alken-3-ols in moderate to excellent yield. Efficient diastereoselective addition to alpha-siloxy and alpha-methylcyclohexanones, as well as protected 3-keto furanose sugars, is achieved in the presence of 10 mol % CeBr3. The resulting bromoallylic alcohol adducts have considerable potential as synthetic building blocks.

  DOI：

  10.1021/ol034594x

文献信息

• 1-Bromo-1-lithioethene:  A Practical Reagent in Organic Synthesis
  作者：Yehor Y. Novikov、Paul Sampson

  DOI：10.1021/jo051125v

  日期：2005.12.1

  A reliable preparative scale synthesis of 1-bromo-1-lithioethene is reported. This reagent undergoes clean 1,2-addition with a range of aldehydes and ketones at -110 degrees C to afford the corresponding 2-bromo-1-alken-3-ols in moderate to excellent yield. Trapping with other electrophiles (acylsilanes, chlorosilanes, tributyltin chloride, iodine) cleanly provides practically useful yields of various 1-substituted 1-bromoethene products. Unexpectedly high diastereoselectivities were observed during the addition of 1-bromo-1-lithioethene to alpha-siloxy aldehydes (typically 10:1, Felkin-Ahn control) and protected ketopyranose and ketofuranose sugars (>= 10:1, addition from the less-hindered face). The title organolithium reagent possesses relatively low basicity at low temperature, and is compatible with a variety of common protecting groups. We believe that these unusual properties of 1-bronio-1-lithioethene may originate from the specific crystalline structure of the reagent in which lithium is coordinatively saturated and thus unavailable for chelation.