2,3-Diphenyl-5,5-dimethyl-1,3,2-oxazaphosphorinane | 133732-94-2

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 氧氮杂膦
• 英文名称: 2,3-Diphenyl-5,5-dimethyl-1,3,2-oxazaphosphorinane
• 英文别名: 5,5-Dimethyl-2,3-diphenyl-1,3,2-oxazaphosphinane；5,5-dimethyl-2,3-diphenyl-1,3,2-oxazaphosphinane
• CAS: 133732-94-2
• 化学式: C₁₇H₂₀NOP
• 分子量: 285.326
• InChiKey: MORHVZQLIKMWNQ-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  4.5
• 重原子数：
  20
• 可旋转键数：
  2
• 环数：
  3.0
• sp3杂化的碳原子比例：
  0.29
• 拓扑面积：
  12.5
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为产物：
  描述：

  2,2-二甲基-3-羟基丙醛 、 alkaline earth salt of/the/ methylsulfuric acid 在 sodium cyanoborohydride 、 zinc(II) chloride 作用下， 以 甲醇 、 乙腈 为溶剂， 反应 252.0h， 生成 2,3-Diphenyl-5,5-dimethyl-1,3,2-oxazaphosphorinane
  参考文献：
  名称：

  X-ray and proton NMR studies of the conformational equilibria of 2-Z-3-phenyl-1,3,2-oxazaphosphorinanes. Steric and stereoelectronic influences on the unexpected axial preferences of Me2N and MeNH substituents on three-coordinate phosphorus

  摘要：

  A series of 2-Z-3-phenyl-1,3,2-oxazaphosphorinanes 7-14 (Z = MeO, (CF3)2CHO, Ph, MeNH, and Me2N) containing three-coordinate phosphorus was prepared. The conformations of the six-membered rings were investigated by H-1 and P-31 NMR spectroscopy and X-ray crystallography. The rings with substituents MeO, (CF3)2CHO, Ph, and MeNH on phosphorus can be unambiguously assigned in solution to a single chair conformation with the substituent of phosphorus axial. An X-ray crystal structure of 5,5-dimethyl-2,3-diphenyl-1,3,2-oxazaphosphorinane, 11, reveals a chair form ring with the phenyl group attached axially to phosphorus. For 13 and 14 with a Me2N substituent on phosphorus, a chair-chair equilibrium (20 reversible 21) is found in solution that features an 80-90% population (DELTAG-degrees = 0.9-1.1 kcal/mol) of the Me2N axial conformation (20). This finding contrasts sharply with the known 1 kcal/mol preference for the Me2N to be equatorial in the corresponding 2-(dimethylamino)-1,3,2-dioxaphosphorinanes. The ability of the 1,3,2-oxazaphosphorinane ring to accommodate the Me2N substituent axially is also seen in the X-ray crystal of 5,5-dimethyl-3-phenyl-2-(dimethylamino)-1,3,2-oxazaphosphorinane, 13, which features a chair conformation ring that is considerably distorted compared to that of 11, quite evidently to allow the Me2N to be in the observed axial orientation, conformation 20. It is argued that the axial orientation of the Me2N in 13 and 14 is at least partly in response to steric repulsions in the alternative chair conformation 21 between the equatorial Me2N and the phenyl substituent at N(3). This effect is in direct contrast to the repulsive interactions between the N(3)Ph and axial Me2N on phosphorus previously demonstrated for four-coordinate, 2-oxo-1,3,2-oxazaphosphorinanes. The increased bond lengths within the 1,3,2-oxazaphosphorinane ring over its 1,3,2-dioxaphosphorinane counterpart (C-N vs C-O) and increased ring flexibility, along with potential n --> sigma* stereoelectronic factors of the type operative in the anomeric effect, are also proposed as potential contributors to the preferred axial orientation of Me2N in 13 and 14. The diastereomeric molecules cis- and trans-5-tert-butyl-3-phenyl-2-(dimethylamino)-1,3,2-oxazaphosphorinane, 17, also were prepared. At thermodynamic equilibrium at room temperature, cis-17 (2-Me2N and 5-t-Bu groups cis) is favored (cis/trans = 80/20). cis-17 displays a conformational equilibrium (Scheme 1) involving a chair conformer (almost-equal-to 60%) with the t-Bu equatorial and Me2N axial, cis-17a, and a single twist or boat form with both substituents pseudoequatorial, cis-17d (almost-equal-to 40%). trans-17 exists in solution in three conformations in approximately equal populations: a chair form with both t-Bu and Me2N equatorial (trans-17a) and two boat/twist forms (trans-17b and trans-17c) with the t-Bu pseudoequatorial and the Me2N pseudoaxial. The distributions of chair and boat/twist conformations can be reasonably understood in terms of the same 1,3-syn axial and vicinal PhN-(3)/Me2N(eq) steric repulsions invoked to explain the chair-chair equilibria noted for the unsubstituted and 5,5-dimethyl-2-(dimethylamino)-3-phenyl-1,3,2-oxazaphosphorinanes 13 and 14. The free energy difference between chair and boat/twist forms evidently is very small.

  DOI：

  10.1021/jo00075a018

文献信息

• X-ray and proton NMR studies of the conformational equilibria of 2-Z-3-phenyl-1,3,2-oxazaphosphorinanes. Steric and stereoelectronic influences on the unexpected axial preferences of Me2N and MeNH substituents on three-coordinate phosphorus
  作者：Yande Huang、Atta M. Arif、Wesley G. Bentrude

  DOI：10.1021/jo00075a018

  日期：1993.11

  A series of 2-Z-3-phenyl-1,3,2-oxazaphosphorinanes 7-14 (Z = MeO, (CF3)2CHO, Ph, MeNH, and Me2N) containing three-coordinate phosphorus was prepared. The conformations of the six-membered rings were investigated by H-1 and P-31 NMR spectroscopy and X-ray crystallography. The rings with substituents MeO, (CF3)2CHO, Ph, and MeNH on phosphorus can be unambiguously assigned in solution to a single chair conformation with the substituent of phosphorus axial. An X-ray crystal structure of 5,5-dimethyl-2,3-diphenyl-1,3,2-oxazaphosphorinane, 11, reveals a chair form ring with the phenyl group attached axially to phosphorus. For 13 and 14 with a Me2N substituent on phosphorus, a chair-chair equilibrium (20 reversible 21) is found in solution that features an 80-90% population (DELTAG-degrees = 0.9-1.1 kcal/mol) of the Me2N axial conformation (20). This finding contrasts sharply with the known 1 kcal/mol preference for the Me2N to be equatorial in the corresponding 2-(dimethylamino)-1,3,2-dioxaphosphorinanes. The ability of the 1,3,2-oxazaphosphorinane ring to accommodate the Me2N substituent axially is also seen in the X-ray crystal of 5,5-dimethyl-3-phenyl-2-(dimethylamino)-1,3,2-oxazaphosphorinane, 13, which features a chair conformation ring that is considerably distorted compared to that of 11, quite evidently to allow the Me2N to be in the observed axial orientation, conformation 20. It is argued that the axial orientation of the Me2N in 13 and 14 is at least partly in response to steric repulsions in the alternative chair conformation 21 between the equatorial Me2N and the phenyl substituent at N(3). This effect is in direct contrast to the repulsive interactions between the N(3)Ph and axial Me2N on phosphorus previously demonstrated for four-coordinate, 2-oxo-1,3,2-oxazaphosphorinanes. The increased bond lengths within the 1,3,2-oxazaphosphorinane ring over its 1,3,2-dioxaphosphorinane counterpart (C-N vs C-O) and increased ring flexibility, along with potential n --> sigma* stereoelectronic factors of the type operative in the anomeric effect, are also proposed as potential contributors to the preferred axial orientation of Me2N in 13 and 14. The diastereomeric molecules cis- and trans-5-tert-butyl-3-phenyl-2-(dimethylamino)-1,3,2-oxazaphosphorinane, 17, also were prepared. At thermodynamic equilibrium at room temperature, cis-17 (2-Me2N and 5-t-Bu groups cis) is favored (cis/trans = 80/20). cis-17 displays a conformational equilibrium (Scheme 1) involving a chair conformer (almost-equal-to 60%) with the t-Bu equatorial and Me2N axial, cis-17a, and a single twist or boat form with both substituents pseudoequatorial, cis-17d (almost-equal-to 40%). trans-17 exists in solution in three conformations in approximately equal populations: a chair form with both t-Bu and Me2N equatorial (trans-17a) and two boat/twist forms (trans-17b and trans-17c) with the t-Bu pseudoequatorial and the Me2N pseudoaxial. The distributions of chair and boat/twist conformations can be reasonably understood in terms of the same 1,3-syn axial and vicinal PhN-(3)/Me2N(eq) steric repulsions invoked to explain the chair-chair equilibria noted for the unsubstituted and 5,5-dimethyl-2-(dimethylamino)-3-phenyl-1,3,2-oxazaphosphorinanes 13 and 14. The free energy difference between chair and boat/twist forms evidently is very small.