sec-butyraldehyde enolate | 136569-10-3

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: sec-butyraldehyde enolate
• 英文别名: But-2-en-2-olate
• CAS: 136569-10-3
• 化学式: C₄H₇O
• 分子量: 71.099
• InChiKey: ZEXFAVZTIZXHFA-UHFFFAOYSA-M

计算性质

• 辛醇/水分配系数(LogP)：
  1.8
• 重原子数：
  5
• 可旋转键数：
  0
• 环数：
  0.0
• sp3杂化的碳原子比例：
  0.5
• 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：

  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
• 作为产物：
  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

文献信息

• Mechanistic studies on gas-phase negative ion unimolecular decompositions. Alkoxide anions
  作者：William. Tumas、Robert F. Foster、John I. Brauman

  DOI：10.1021/ja00217a003

  日期：1988.4

  Les ions alcoolates subissent une elimination de molecules neutres pour donner des ions enolates

  Les ion alcoolates subissent une demoles neutres pour donner des ions enolates
• Hydride transfer to transition-metal carbonyls in the gas phase. Formation and relative stabilities of anionic formyl complexes
  作者：Kelley R. Lane、Robert R. Squires

  DOI：10.1016/s0277-5387(00)81786-6

  日期：1988.1

  of Fe(CO) 5 , Cr(CO) 6 , Mo(CO) 6 and W(CO) 6 ( HA (M(CO) n ) = D[(CO) n − MCOH − ]) have been estimated from bimolecular hydride transfer reactions in the gas phase. Hydride transfer to the metal carbonyls yields the corresponding anionic formyl complexes and the hydride affinity bracketing experiments establish HA (Fe(CO) 5 ) = 56±4 kcal mol −1 and HA (Cr(CO) 6 ) = HA (Mo(CO) 6 ) = HA (W(CO) 6 )

  摘要Fe（CO）5，Cr（CO）6，Mo（CO）6和W（CO）6（HA（M（CO）n）= D [（CO）n-MCOH- ]）是根据气相中的双分子氢化物转移反应估算的。氢化物转移到羰基金属上产生相应的阴离子甲酰基络合物，氢化物亲和力包围实验建立HA（Fe（CO）5）= 56±4 kcal mol -1和HA（Cr（CO）6）= HA（Mo（CO ）6）= HA（W（CO）6）= 44±4 kcal mol -1。金属甲酰基阴离子的气相形成热和金属-碳键强度来自氢化物结合能。金属羰基化合物的氢化物亲和力排序与它们对溶液中亲核加成反应的相对反应性平行，并且与它们的CO拉伸力常数的相对大小（k co）相关。
• Mercer, Roger S.; Harrison, Alex G., Canadian Journal of Chemistry, 1988, vol. 66, p. 2947 - 2953
  作者：Mercer, Roger S.、Harrison, Alex G.

  DOI：——

  日期：——
• Hydride transfer to transition-metal carbonyls in the gas phase. The heat of formation of (CO)4FeCHO-
  作者：Kelley R. Lane、Larry Sallans、Robert R. Squires

  DOI：10.1021/om00121a042

  日期：1985.2
• 1,2-Versus 1,4-reduction of α,β-unsaturated carbonyl compounds in the gas phase
  作者：Yeunghaw Ho、Robert R. Squires

  DOI：10.1002/oms.1210281243

  日期：1993.12

  AbstractThe regioselectivity involved in the gas‐phase hydride reduction of α,β‐unsaturated carbonyl compounds by pentacoordinate silicon hydride ions is investigated. The kinetics and product distributions of the reactions of acrolein, methyl vinyl ketone and cyclohex‐2‐enone with monoalkoxysiliconate ions of the general composition RSiH3(OR′)− were examined with the flowing afterglow–triple quadrupole technique. All three substrates react by hydride transfer and by formation of a siliconate adduct in which hydride reduction of the organic reactant has occurred. The structures of these adducts and the hydride transfer products were identified by various tandem mass spectrometric protocols, including analysis of competitive collision‐induced dissociation (CID) reactions and comparisons of CID spectra obtained from reference ions with known structures. 1,4‐Reduction forming an enolate ion product is found to be the dominant or exclusive process with all three substrates, i.e. acrolein (70 ± 5%), methyl vinyl ketone (72 ± 5%) and cyclohex‐2‐enone (100%). Comparisons are made between these gas‐phase results and the regioselectivity reported for analogous condensed‐phase reactions. The observed behavior is discussed in terms of the reaction thermochemistry.