1-ethoxy-2-methylenebicyclo<2.2.2>octane | 137495-16-0

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: 1-ethoxy-2-methylenebicyclo<2.2.2>octane
• 英文别名: 1-Ethoxy-2-methylidenebicyclo[2.2.2]octane
• CAS: 137495-16-0
• 化学式: C₁₁H₁₈O
• 分子量: 166.263
• InChiKey: INESXSLMKWTBKI-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2.1
• 重原子数：
  12
• 可旋转键数：
  2
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.82
• 拓扑面积：
  9.2
• 氢给体数：
  0
• 氢受体数：
  1

反应信息

• 作为产物：
  描述：

  2-methylenebicyclo<2.2.2>oct-1-yl triflate 、 乙醇 在 2,6-二甲基吡啶 作用下， 反应 20.0h， 以71%的产率得到1-ethoxy-2-methylenebicyclo<2.2.2>octane
  参考文献：
  名称：

  Solvolysis of 2-methylene bicyclic bridgehead derivatives: a model for gradual variation of .pi.-conjugation in carbocations

  摘要：

  The rates of solvolysis in ethanol or 80% ethanol at 25-degrees-C have been determined on 2-methylenebicyclo[2.2.2]oct-1-yl triflate (4a), 2-methylenebicyclo[3.2.1]oct-1-yl triflate (5a), 2-methylenebicyclo[3.2.2]non-1-yl mesylate (6a), 2-methylenebicyclo[3.3.1]non-1-yl mesylate (7a-OMs) and heptafluorobutyrate (7a-OHFB), 1-chloro-2-methylenebicyclo[4.2.2]decane (8a), 2-methylenebicyclo[4.3.1]dec-1-yl trifluoroacetate (9a), and 4-methylene-3-homoadamantyl heptafluorobutyrate (10a) and on their corresponding parent 1-bicycloalkyl and 3-homoadamantyl derivatives 4b-10b containing the respective leaving group. The rate ratios for 4a/4b, 5a/5b, 10a/10b, 6a/6b, 7a/7b, 8a/8b, and 9a/9b are 10(-3.9), 10(-1.9), 10(-1.1), 10(0.8), 10(0.9) (for mesylate), 10(-0.2), and 10(0.7), respectively. A plot of the logarithms of the rate ratios against olefinic strain energies of their corresponding unsubstituted bridgehead olefins shows that the smaller the olefinic strain energy, the greater the rate ratio, providing a methodology to gradually change the conjugative ability of bridgehead carbocations. The enhancement of allylic conjugation with increasing skeletal flexibility has been further verified by the enhanced solvolysis rate of (E)-2-ethylidenebicyclo[3.2.2]non-1-yl mesylate ((E)-6e) relative to 6a by a factor of 259. A similar study on much more rigid (E)-2-ethylidenebicyclo[2.2.2]oct-1-yl triflate ((E)-4e) gave a (E)-4e/4a rate ratio of 6.3. AM1 semiempirical molecular orbital calculations on pertinent 2-methylene and (E)-2-ethylidene bridgehead carbocations and corresponding hydrocarbons (L = hydrogen) also supported the increase in the conjugation with increasing skeletal flexibility. The solvolysis products were solely bridgehead substitution products, no indication for the formation of bridgehead olefin via an S(N)1' mechanism having been obtained.

  DOI：

  10.1021/jo00027a050

文献信息

• Solvolyses of Bicyclo[2.2.2]oct-1-yl and 1-Adamantyl Systems Containing an Ethylidene Substituent on the 2-Position: Typical Examples of Rate Enhancements Ascribed to Relief of F-Strain
  作者：Yasushi Ohga、Motohiro Munakata、Toshikazu Kitagawa、Tomomi Kinoshita、Ken'ichi Takeuchi、Yasuo Oishi、Hiroshi Fujimoto

  DOI：10.1021/jo00094a012

  日期：1994.7

  The first typical examples are described on the solvolysis rate enhancements ascribed to the relief of F-strain between an alkyl group and the leaving group atom directly attached to the reaction center. The rates and products of solvolyses in ethanol were studied for 2-methylene- and (Z)- and (E)-2-ethylidenebicyclo[2.2.2]oct-1-yl triflates. Solvolyses were also conducted in ethanol and 2,2,2-trifluoroethanol (TFE) on 2-methylene- and (Z)- and (E)-2-ethylidene-1-adamantyl compounds having OMs, F, Cl, Br, or I asa leaving group. Ah the substrates gave the corresponding bridgehead substitution products as kinetic control products. The Z:E rate ratios at 25 degrees C were 217 +/- 6 for 2-ethylidenebicyclo[2.2.2]oct-1-yl triflates (ethanol) and 109 +/- Il(ethanol) and 117 fl(TFE)for 2-ethylidene-1-adamantyl mesylates. O-18 scrambling studies on the ethanolyses of(Z)- and (E)2-ethylidene-1-adamantyl mesylates showed that the titrimetrically determined Z:E rate ratios can be used as a measure of the rate ratios for the ionization step. The Z:E rate ratio in TFE at 25 degrees C for 2-ethylidene-1-adamantyl halides varied in the sequence F (ca. 70), Cl(1020 +/- 160), Br (2230 +/- 90), and I (9500 +/- 280). The significant increases in the rate ratio with the increase in the atomic size of halogen were explained in terms of the presence of F-strain in the Z substrates and its essential absence in the E substrates. Linear correlations were found in a plot of 1.36 x log[k(Z)/k(E)] against the MM2 steric energy difference between the Z and E isomers (slope 1.0) and against Hansch's Es, demonstrating the significance of F-strain effect in the enhanced rates of the (Z)-2-ethylidene-1-adamantyl system. These correlations showed an intercept of 0.8 kcal mol(-1), which suggested the greater stability of the (Z)-2-ethylidene-1-adamantyl cation than the corresponding E cation by this amount. Ab initio calculations (RHF/G-31G**) showed that the Z cation is more stable than the E cation by 1.0 kcal mol(-1), and that the large Z:E rate ratios are in part ascribed to the difference in the cation stability.
• TAKEUCHI, KENICHI;YOSHIDA, MASAYASU, J. ORG. CHEM., 54,(1989) N6, C. 3772-3773
  作者：TAKEUCHI, KENICHI、YOSHIDA, MASAYASU

  DOI：——

  日期：——