(R)-2-Methylene-1,3-diphenyl-heptan-1-one | 143008-44-0

• 分子结构分类: 有机化合物 - 木脂素、新木脂素和相关化合物
• 英文名称: (R)-2-Methylene-1,3-diphenyl-heptan-1-one
• 英文别名: (3R)-2-methylidene-1,3-diphenylheptan-1-one
• CAS: 143008-44-0
• 化学式: C₂₀H₂₂O
• 分子量: 278.394
• InChiKey: HWIJJONYRHQLPI-IBGZPJMESA-N

计算性质

• 辛醇/水分配系数(LogP)：
  6.1
• 重原子数：
  21
• 可旋转键数：
  7
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.25
• 拓扑面积：
  17.1
• 氢给体数：
  0
• 氢受体数：
  1

反应信息

• 作为产物：
  描述：

  α-(nitromethyl)chalcone 在 lithium bromide 作用下， 以 乙腈 为溶剂， 反应 2.17h， 生成 (R)-2-Methylene-1,3-diphenyl-heptan-1-one
  参考文献：
  名称：

  Asymmetric synthesis of 3-substituted 2-exo-methylenealkanones by addition-elimination reaction using a chiral leaving group and organometallic nucleophiles

  摘要：

  A novel diastereodifferentiating addition-elimination reaction of (S)-2-[[2-(methoxymethyl)-1-pyrrolidinyl]methyl]-2-alken-1-ones with organometallic reagents such as organocuprates and organozincates afforded optically active 3-substituted 2-methylenealkanones with high enantiomeric purity. The enantiomeric excess (ee) of the products in this asymmetric induction reaction involving 1,5-transfer of stereogenicity was highly dependent on the structure of the enone substrates and the type of organometallic reagents, chiral auxiliaries, and added Lewis acids: (i) the use of lithium diorganocuprates (R2CuLi) led to the highest ee's, (ii) in the reaction with R2CuLi the ee decreased in the following order by varying their structure of the main framework of the enones, cycloheptenones (96-97% ee) > cyclohexenones (95% ee) > cyclopentenones (82-85% ee) > acyclic enones (55-70% ee), (iii) the addition of LiBr as the external Lewis acid in the reaction with R2CuLi did not affect the ee, whereas that of ZnBr2 or MgBr2 decreased the ee by 5% or considerably more, respectively, and (iv) the existence of the methoxy oxygen atom in the chiral auxiliary was essential to achieve high ee's. The origin of the observed high and low ee's was rationalized by considering plausible transition state models.

  DOI：

  10.1021/jo00044a026