(+/-)-3-epi-Acetomycin

• 分子结构分类: 有机化合物 - 有机酸及其衍生物 - 羧酸及其衍生物
• 英文名称: (+/-)-3-epi-Acetomycin
• 英文别名: [(2R,3S,4R)-4-acetyl-3,4-dimethyl-5-oxooxolan-2-yl] acetate
• 化学式: C₁₀H₁₄O₅
• 分子量: 214.218
• InChiKey: OYMZTORLGBISLR-DPKJLXEKSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1
• 重原子数：
  15
• 可旋转键数：
  3
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.7
• 拓扑面积：
  69.7
• 氢给体数：
  0
• 氢受体数：
  5

反应信息

• 作为产物：
  描述：

  4-Methyl-5-acetoxy-2-furanone 在 palladium on activated charcoal 氢气 、 lithium hexamethyldisilazane 作用下， 以 四氢呋喃 、 甲醇 为溶剂， 反应 7.53h， 生成 (+/-)-3-epi-Acetomycin
  参考文献：
  名称：

  Unexpected Contrasteric Alkylation Leading to a Model for Five-Membered Ring Enolate Alkylation: Short Stereoselective Synthesis of (.+-.)-Acetomycin

  摘要：

  It is well established that the alkylation of cyclic enolates 1 bearing an asymmetric center at the beta-position should provide mainly lactones 2 where the electrophile (E(+)) ends up trans to the beta-substituent (R(2)). Our interest in such processes lies in the fact that according to this principle, alkylation of 1a with methyl iodide should provide direct access to (+/-)-acetomycin (2a). However, this reaction unexpectedly afforded the contrasteric alkylation product 3a ((+/-)-3-epi-acetomycin) with high diastereoselectivity. To elucidate this observation, alkylation studies have been carried out on various enolates 1. As normally expected, when R(2) and R(3) are alkyl groups, only product 2 is obtained. On the other hand, when R(3) is an acetoxy or an alkoxy group and methyl iodide is used as electrophile, the contrasteric products 3 are predominant. With sterically more demanding electrophiles, the ''normal'' alkylation products 2 are obtained in moderate to extremely high selectivity. Thus, the use of 1,3-dithienium tetrafluoroborate, a bulky methyl equivalent, allowed us to complete a stereoselective synthesis of(+/-)-acetomycin. These results led to the elaboration of a model for five-membered ring enolate alkylation based on steric and stereoelectronic effects, as well as ring conformations.

  DOI：

  10.1021/jo00121a025

文献信息

• Stereoselective Synthesis of (±)-4-epi-acetomycin by the ester enolate carroll rearrangement
  作者：Antonio M. Echavarren、Javier de Mendoz、Pilar Prados、Amparo Zapata

  DOI：10.1016/0040-4039(91)80185-9

  日期：1991.10

  The synthesis of (+-)-4-epi-acetomycin has been completed by the steroselective ester enolate (Carroll rearrangement of (E)-2-butenyl 2-methylacetoacetate, followed by ozonolysis and acetylation. The synthesis of (±)- acetomycin and its three diastereomers by a related route is also described.

  （+-）-4-epi-acetomycin的合成已通过立体选择性酯烯酸酯完成（（E）-2-丁烯基-2-甲基乙酰乙酸的卡洛尔重排，然后进行臭氧分解和乙酰化。还描述了其三个非对映异构体的相关路线。