| 64723-94-0

• 分子结构分类: 有机化合物 - 有机氧化合物
• CAS: 64723-94-0
• 化学式: C₄H₇O
• 分子量: 71.099
• InChiKey: WQNSWDQDVWAIJG-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  0.8
• 重原子数：
  5.0
• 可旋转键数：
  1.0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.5
• 拓扑面积：
  17.07
• 氢给体数：
  0.0
• 氢受体数：
  1.0

反应信息

• 作为反应物：
  描述：

  在 甲醇 作用下， 生成 sec-butyraldehyde enolate
  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：

  sec-butyraldehyde enolate 在 甲醇 作用下， 生成
  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

• Hypovalent radicals. 13. Gas-phase nucleophilic reactivities of phenylnitrene (PhN^- •) and sulfur anion radicals (S^-•) at sp³ and carbonyl carbon
  作者：Richard N. McDonald、A. Kasem Chowdhury

  DOI：10.1021/ja00340a010

  日期：1983.1
• 1,3-Hydrogen Rearrangements of Vibrationally Activated Enolate Ions in the Gas Phase
  作者：Kristin A. Sannes、John I. Brauman

  DOI：10.1021/ja00145a020

  日期：1995.10

  The unimolecular rearrangement reactions of the isomeric enolate ions of 2-butanone have been investigated using Fourier transform ion cyclotron resonance mass spectrometry and infrared multiple photon activation techniques. The individual isomers of 2-butanone enolate ions were generated from the corresponding trimethylsilyl enol ethers and photodissociated independently. Infrared multiple photon activation of the 2-butanone enolate ions induces a 1,3-hydrogen rearrangement which interconverts the individual isomers. Because infrared multiple photon activation only involves vibrational excitation, the 1,3-hydrogen rearrangement must be a thermal reaction and occur on the ground electronic state potential energy surface. The observation of a 1,3-hydrogen rearrangement is unexpected and appears to violate the Woodward-Hoffmann symmetry rules. Orbital correlation diagrams show, however, that thermal suprafacial 1,3-hydrogen rearrangements are allowed for enolic systems. Nevertheless, a more probable reaction mechanism involves the rotation of the methylene groups so that the 1,3-hydrogen rearrangement corresponds to a simple proton transfer between two unsaturated carbons.
• 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.