dimethylacetonide | 138999-31-2

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: dimethylacetonide
• 英文别名: 3-Methylbut-1-en-2-olate；3-methylbut-1-en-2-olate
• CAS: 138999-31-2
• 化学式: C₅H₉O
• 分子量: 85.1259
• InChiKey: NSPPRYXGGYQMPY-UHFFFAOYSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  2.3
• 重原子数：
  6
• 可旋转键数：
  1
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.6
• 拓扑面积：
  23.1
• 氢给体数：
  0
• 氢受体数：
  1

反应信息

• 作为反应物：
  描述：

  dimethylacetonide 在 甲醇 作用下， 生成 dimethyl-acetonide
  参考文献：
  名称：

  Kinetic versus Thermodynamic Control in the Deprotonation of Unsymmetrical Ketones in the Gas Phase

  摘要：

  An experimental method is presented for determining the regioselectivity of deprotonation of unsymmetrical ketones in the gas phase. Mixtures of tautomeric enolate ions were prepared in a flowing afterglow apparatus and then assayed through a reaction with n-butyl nitrite in the collision cell of a triple quadrupole mass analyzer. Enolate ions were also prepared regioselectively by desilylation of the corresponding trimethylsilyl enol ethers with fluoride ion. Rate coefficients for the methanol-catalyzed tautomerization of the regioisomers were measured and were used to derive the equilibrium ratio of the tautomers. For 2-butanone it was found that the equilibrium mixture of enolate ions consisted of 55% of the more substituted isomer. For 3-methyl-2-butanone and 2-methyl-3-pentanone the equilibrium mixture comprised greater than 95% of the less substituted isomer. Several different bases were used to prepare nonequilibrium mixtures of enolate ions. Strong bases deprotonate these ketones irreversibly and in a statistical fashion. Deprotonation with hindered bases altered the composition of regioisomers only slightly. Ab initio molecular orbital calculations were performed on 2-butanone, 3-methyl-2-butanone, and their corresponding enolate ions at the MP4SDQ/ 6-31+G(d)//HF/6-31+G(d) level of theory. For 2-butanone, the calculations predict that the Z secondary enolate and the primary enolate have equal stabilities (Delta E < 0.1 kcal/mol), while the E secondary enolate is 4.1 kcal/mol higher in energy than the Z enolate ion. For 3-methyl-2-butanone, the tertiary enolate ion is calculated to be 4.3 kcal/mol higher in energy than the primary enolate ion. The computed gas-phase acidities of the two ketones are in excellent agreement with the experimentally determined values.

  DOI：

  10.1021/ja00098a031
• 作为产物：
  描述：

  dimethyl-acetonide 在 甲醇 作用下， 生成 dimethylacetonide
  参考文献：
  名称：

  Kinetic versus Thermodynamic Control in the Deprotonation of Unsymmetrical Ketones in the Gas Phase

  摘要：

  An experimental method is presented for determining the regioselectivity of deprotonation of unsymmetrical ketones in the gas phase. Mixtures of tautomeric enolate ions were prepared in a flowing afterglow apparatus and then assayed through a reaction with n-butyl nitrite in the collision cell of a triple quadrupole mass analyzer. Enolate ions were also prepared regioselectively by desilylation of the corresponding trimethylsilyl enol ethers with fluoride ion. Rate coefficients for the methanol-catalyzed tautomerization of the regioisomers were measured and were used to derive the equilibrium ratio of the tautomers. For 2-butanone it was found that the equilibrium mixture of enolate ions consisted of 55% of the more substituted isomer. For 3-methyl-2-butanone and 2-methyl-3-pentanone the equilibrium mixture comprised greater than 95% of the less substituted isomer. Several different bases were used to prepare nonequilibrium mixtures of enolate ions. Strong bases deprotonate these ketones irreversibly and in a statistical fashion. Deprotonation with hindered bases altered the composition of regioisomers only slightly. Ab initio molecular orbital calculations were performed on 2-butanone, 3-methyl-2-butanone, and their corresponding enolate ions at the MP4SDQ/ 6-31+G(d)//HF/6-31+G(d) level of theory. For 2-butanone, the calculations predict that the Z secondary enolate and the primary enolate have equal stabilities (Delta E < 0.1 kcal/mol), while the E secondary enolate is 4.1 kcal/mol higher in energy than the Z enolate ion. For 3-methyl-2-butanone, the tertiary enolate ion is calculated to be 4.3 kcal/mol higher in energy than the primary enolate ion. The computed gas-phase acidities of the two ketones are in excellent agreement with the experimentally determined values.

  DOI：

  10.1021/ja00098a031

文献信息

• Beugelmans, Rene, Bulletin des Societes Chimiques Belges, 1984, vol. 93, # 7, p. 547 - 558
  作者：Beugelmans, Rene

  DOI：——

  日期：——
• Kinetic versus Thermodynamic Control in the Deprotonation of Unsymmetrical Ketones in the Gas Phase
  作者：Leonard J. Chyall、Mark D. Brickhouse、Mark E. Schnute、Robert R. Squires

  DOI：10.1021/ja00098a031

  日期：1994.9

  An experimental method is presented for determining the regioselectivity of deprotonation of unsymmetrical ketones in the gas phase. Mixtures of tautomeric enolate ions were prepared in a flowing afterglow apparatus and then assayed through a reaction with n-butyl nitrite in the collision cell of a triple quadrupole mass analyzer. Enolate ions were also prepared regioselectively by desilylation of the corresponding trimethylsilyl enol ethers with fluoride ion. Rate coefficients for the methanol-catalyzed tautomerization of the regioisomers were measured and were used to derive the equilibrium ratio of the tautomers. For 2-butanone it was found that the equilibrium mixture of enolate ions consisted of 55% of the more substituted isomer. For 3-methyl-2-butanone and 2-methyl-3-pentanone the equilibrium mixture comprised greater than 95% of the less substituted isomer. Several different bases were used to prepare nonequilibrium mixtures of enolate ions. Strong bases deprotonate these ketones irreversibly and in a statistical fashion. Deprotonation with hindered bases altered the composition of regioisomers only slightly. Ab initio molecular orbital calculations were performed on 2-butanone, 3-methyl-2-butanone, and their corresponding enolate ions at the MP4SDQ/ 6-31+G(d)//HF/6-31+G(d) level of theory. For 2-butanone, the calculations predict that the Z secondary enolate and the primary enolate have equal stabilities (Delta E < 0.1 kcal/mol), while the E secondary enolate is 4.1 kcal/mol higher in energy than the Z enolate ion. For 3-methyl-2-butanone, the tertiary enolate ion is calculated to be 4.3 kcal/mol higher in energy than the primary enolate ion. The computed gas-phase acidities of the two ketones are in excellent agreement with the experimentally determined values.