4-bromo-3,5-di-tert-butyl-5-fluoro-2-phenyl-1,2-oxaphosphol-3-ene 2-oxide | 141091-52-3

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯和取代衍生物
• 英文名称: 4-bromo-3,5-di-tert-butyl-5-fluoro-2-phenyl-1,2-oxaphosphol-3-ene 2-oxide
• 英文别名: 4-Bromo-3,5-di-tert-butyl-5-fluoro-2-phenyl-2,5-dihydro-1,2-oxaphosphole 2-oxide；4-bromo-3,5-ditert-butyl-5-fluoro-2-phenyl-1,2λ5-oxaphosphole 2-oxide
• CAS: 141091-52-3
• 化学式: C₁₇H₂₃BrFO₂P
• 分子量: 389.245
• InChiKey: VIAXKCVQAGAVNG-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  5.1
• 重原子数：
  22
• 可旋转键数：
  3
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.53
• 拓扑面积：
  26.3
• 氢给体数：
  0
• 氢受体数：
  3

反应信息

• 作为产物：
  描述：

  (E)-4,5-dibromo-3,5-di-tert-butyl-2-phenyl-1,2-oxaphosphol-3-ene 2-oxide 在 silver tetrafluoroborate 作用下， 以 四氢呋喃 为溶剂， 反应 0.08h， 生成 4-bromo-3,5-di-tert-butyl-5-fluoro-2-phenyl-1,2-oxaphosphol-3-ene 2-oxide
  参考文献：
  名称：

  Reactions of 1,2-oxaphospholenes. 7. Anomalous low reactivity of a tertiary allylic bromide. The crystal and molecular structure of (E)-4,5-dibromo-3,5-di-tert-butyl-2-phenyl-1,2-oxaphosphol-3-ene 2-oxide

  摘要：

  Reaction of 2,2,6,6-tetramethyl-4-heptyn-3-ol (5) with dichlorophenylphosphine leads to (2,2,6,6-tetramethyl-3,4-heptadien-3-yl)phenylphosphinic acid (7), which undergoes Ag+-catalyzed cyclization to 3,4-di-tert-butyl-2-phenyl-1,2-oxaphosphol-3-ene 2-oxide (1e, 75-55% Z, 25-45% E). Electrophilic bromination of 7 affords 1f, the 4-bromo derivative of 1e, as a 75% Z, 25% E diastereomer mixture from which pure (Z)-1f can be isolated. Free radical allylic bromination of 1e and 1f leads to the corresponding 5-bromo derivatives 2e and 2f, each as a single diastereomer. X-ray analysis proved that 2f has the E configuration, which is therefore also assigned to 2e. All other diastereomeric configurations were assigned on the basis of H-1 NMR. Allylic bromide (E)-2e is at least 1700 times more reactive than (E)-2f toward methanolysis, though both yield the corresponding 5-methoxy derivatives ((Z-4e and (Z)-4f) with inversion of configuration. The retardation of (E)-2f relative to (E)-2e is ascribed to steric interference between the C4 bromine and the C5 tert-butyl group in the methanolysis intermediate (3f), an effect which is supported by a low-temperature H-1 NMR study of (E)-2f. Reaction of (E)-2f with AgBF4 or AgOTFA in THF gives the 5-fluoro and 5-trifluoroacetoxy derivatives, respectively, further indication of the instability of 3f. P-31 NMR indicates that the phosphoryl oxygen in (E)-2f can be reductively cleaved by DIBALH, but the resulting product is quickly reoxidized to (E/Z)-2f by air. Reaction of (E)-2f with NaBH4 leads to reductive cleavage of the C4 bromine, as well as the C5 bromine, leading to the formation of 1e, 1f, and 4e. Extended Huckel calculations are in agreement with the stereochemical preferences observed in this work, as well as the solvolysis rate-retarding effect of the phosphoryl oxygen. In view of the dramatic solvolysis rate reduction caused by the 4-bromo group in (E)-2f and related compounds, the normal solvolytic reactivity of 2c, the 2-hydroxy analogue of 2f, is ascribed to a mechanism involving reversible ring opening.

  DOI：

  10.1021/jo00040a029

文献信息

• Reactions of 1,2-oxaphospholenes. 7. Anomalous low reactivity of a tertiary allylic bromide. The crystal and molecular structure of (E)-4,5-dibromo-3,5-di-tert-butyl-2-phenyl-1,2-oxaphosphol-3-ene 2-oxide
  作者：Roger S. Macomber、Daniel E. Rardon、Douglas M. Ho

  DOI：10.1021/jo00040a029

  日期：1992.7

  Reaction of 2,2,6,6-tetramethyl-4-heptyn-3-ol (5) with dichlorophenylphosphine leads to (2,2,6,6-tetramethyl-3,4-heptadien-3-yl)phenylphosphinic acid (7), which undergoes Ag+-catalyzed cyclization to 3,4-di-tert-butyl-2-phenyl-1,2-oxaphosphol-3-ene 2-oxide (1e, 75-55% Z, 25-45% E). Electrophilic bromination of 7 affords 1f, the 4-bromo derivative of 1e, as a 75% Z, 25% E diastereomer mixture from which pure (Z)-1f can be isolated. Free radical allylic bromination of 1e and 1f leads to the corresponding 5-bromo derivatives 2e and 2f, each as a single diastereomer. X-ray analysis proved that 2f has the E configuration, which is therefore also assigned to 2e. All other diastereomeric configurations were assigned on the basis of H-1 NMR. Allylic bromide (E)-2e is at least 1700 times more reactive than (E)-2f toward methanolysis, though both yield the corresponding 5-methoxy derivatives ((Z-4e and (Z)-4f) with inversion of configuration. The retardation of (E)-2f relative to (E)-2e is ascribed to steric interference between the C4 bromine and the C5 tert-butyl group in the methanolysis intermediate (3f), an effect which is supported by a low-temperature H-1 NMR study of (E)-2f. Reaction of (E)-2f with AgBF4 or AgOTFA in THF gives the 5-fluoro and 5-trifluoroacetoxy derivatives, respectively, further indication of the instability of 3f. P-31 NMR indicates that the phosphoryl oxygen in (E)-2f can be reductively cleaved by DIBALH, but the resulting product is quickly reoxidized to (E/Z)-2f by air. Reaction of (E)-2f with NaBH4 leads to reductive cleavage of the C4 bromine, as well as the C5 bromine, leading to the formation of 1e, 1f, and 4e. Extended Huckel calculations are in agreement with the stereochemical preferences observed in this work, as well as the solvolysis rate-retarding effect of the phosphoryl oxygen. In view of the dramatic solvolysis rate reduction caused by the 4-bromo group in (E)-2f and related compounds, the normal solvolytic reactivity of 2c, the 2-hydroxy analogue of 2f, is ascribed to a mechanism involving reversible ring opening.