(1R,3R,5S)-1,4,4-trimethylspiro[bicyclo[3.2.1]octane-3,2'-oxolane]-2-one | 141636-13-7

• 分子结构分类: 有机化合物 - 脂质和类脂质分子 - 异戊烯醇脂质
• 英文名称: (1R,3R,5S)-1,4,4-trimethylspiro[bicyclo[3.2.1]octane-3,2'-oxolane]-2-one
• CAS: 141636-13-7
• 化学式: C₁₄H₂₂O₂
• 分子量: 222.327
• InChiKey: VTJDQIZXVRFQIR-GDLCADMTSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.8
• 重原子数：
  16
• 可旋转键数：
  0
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.93
• 拓扑面积：
  26.3
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  (1R,3R,5S)-1,4,4-trimethylspiro[bicyclo[3.2.1]octane-3,2'-oxolane]-2-one 在 ion exchange resin (Amberlyst 15) 、 叔丁基锂 作用下， 以 二氯甲烷 为溶剂， 反应 0.5h， 生成
  参考文献：
  名称：

  Regio- and stereochemical course of the ring expansion of bridged bicyclic ketones to spirocyclic .alpha.-keto tetrahydrofurans.

  摘要：

  The regio- and stereochemical aspects of oxonium-promoted pinacol-like rearrangements have been investigated starting from the bridged bicyclic ketones (+/-)-norcamphor, (1R)-(-)-fenchone, and (1R)-(-)-3,3-dimethyl-1-vinyl-2-norbornanone. 1,2-Addition of 5-lithio-2,3-dihydrofuran to these substrates provided alcohols that smoothly underwent acid-catalyzed ring expansion. Whereas bridgehead carbon migration was observed in the first and third examples, the alternative available 1,2 Wagner-Meerwein shift operated in the fenchone series. In every instance, a substantial kinetic preference for formation of the O-exo spirotetrahydrofuranyl ketone was noted. Positioning of the dihydrofuranyl unit in sterically congested endo environments as accomplished by condensation of the alpha-lithio vinyl ether with (1R)-(+)-camphor, (1S)-(+)-7,7-dimethyl-1-vinyl-2-norbornanone, and (1s)-(-)-apocamphor was accompanied by increased hydrolytic sensitivity. Second-stage ring expansion of two of the spirocyclic ketones was characterized by continued adherence to anticipated migratory aptitudes. However, loss of stereochemistry occurred both at the original alpha-carbon and at the newly introduced stereogenic center. These observations and relevant control experiments are most consistent with a push-pull fragmentation scheme leading to a ring-opened oxonium ion-enol pair that, because they are tethered, find it possible to cyclize. Prior to final bonding, either terminus may rotate relative to the other. The kinetic and thermodynamic interrelationships of these phenomena are discussed.

  DOI：

  10.1021/jo00040a042
• 作为产物：
  描述：

  (1R,2R,4S)-2-(4,5-dihydro-2-furyl)-1,3,3-trimethyl-2-norbornanol 在 对甲苯磺酸 作用下， 以 氯仿 为溶剂， 以69%的产率得到(1R,3R,5S)-1,4,4-trimethylspiro[bicyclo[3.2.1]octane-3,2'-oxolane]-2-one
  参考文献：
  名称：

  Regio- and stereochemical course of the ring expansion of bridged bicyclic ketones to spirocyclic .alpha.-keto tetrahydrofurans.

  摘要：

  The regio- and stereochemical aspects of oxonium-promoted pinacol-like rearrangements have been investigated starting from the bridged bicyclic ketones (+/-)-norcamphor, (1R)-(-)-fenchone, and (1R)-(-)-3,3-dimethyl-1-vinyl-2-norbornanone. 1,2-Addition of 5-lithio-2,3-dihydrofuran to these substrates provided alcohols that smoothly underwent acid-catalyzed ring expansion. Whereas bridgehead carbon migration was observed in the first and third examples, the alternative available 1,2 Wagner-Meerwein shift operated in the fenchone series. In every instance, a substantial kinetic preference for formation of the O-exo spirotetrahydrofuranyl ketone was noted. Positioning of the dihydrofuranyl unit in sterically congested endo environments as accomplished by condensation of the alpha-lithio vinyl ether with (1R)-(+)-camphor, (1S)-(+)-7,7-dimethyl-1-vinyl-2-norbornanone, and (1s)-(-)-apocamphor was accompanied by increased hydrolytic sensitivity. Second-stage ring expansion of two of the spirocyclic ketones was characterized by continued adherence to anticipated migratory aptitudes. However, loss of stereochemistry occurred both at the original alpha-carbon and at the newly introduced stereogenic center. These observations and relevant control experiments are most consistent with a push-pull fragmentation scheme leading to a ring-opened oxonium ion-enol pair that, because they are tethered, find it possible to cyclize. Prior to final bonding, either terminus may rotate relative to the other. The kinetic and thermodynamic interrelationships of these phenomena are discussed.

  DOI：

  10.1021/jo00040a042