1-p-methoxyphenyl-2,2-dimethylvinyl cation | 74975-64-7

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯酚醚
• 英文名称: 1-p-methoxyphenyl-2,2-dimethylvinyl cation
• 英文别名: 1-Methoxy-4-(2-methylprop-1-enyl)benzene
• CAS: 74975-64-7
• 化学式: C₁₁H₁₃O
• 分子量: 161.224
• InChiKey: RKDZDWBLWPKONU-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  3.9
• 重原子数：
  12
• 可旋转键数：
  2
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.27
• 拓扑面积：
  9.2
• 氢给体数：
  0
• 氢受体数：
  1

反应信息

• 作为反应物：
  描述：

  2,2,2-三氟乙醇 、 1-p-methoxyphenyl-2,2-dimethylvinyl cation 生成
  参考文献：
  名称：

  为什么乙烯基阳离子是缓慢的亲电试剂？

  摘要：

  乙烯基阳离子 2 [Ph2C=C+-(4-MeO-C6H4)] 和 3 [Me2C=C+-(4-MeO-C6H4)]（由激光闪光光解产生）与多种亲核试剂（例如、吡咯、卤化物离子和含有不同量水或醇的溶剂）已通过光度法测定。发现亲核试剂对这些乙烯基阳离子的反应顺序与对二芳基碳鎓离子（二苯甲基鎓离子）的反应顺序相同。然而，乙烯基阳离子的反应速率受亲核试剂变化的影响仅是二苯甲基离子的反应速率的一半。因此，乙烯基阳离子和二苯甲基离子的相对反应性在很大程度上取决于亲核试剂的性质。结果表明，乙烯基阳离子 2 和 3 分别反应，使用三氟乙醇比母体二苯鎓离子 (Ph)2CH+ 慢 227 和 14 倍，即使在溶剂分解反应（25°C 时为 80% 乙醇水溶液）中，导致 2 和 3 的乙烯基溴离子化得更慢（半衰期 1.15年和 33 天）比 (Ph)2CH-Br（半衰期 23 秒）。通过高级 MO 计算研究了这

  DOI：

  10.1021/jacs.6b10889
• 作为产物：
  描述：

  1-(1-溴-2-甲基丙-1-烯基)-4-甲氧基苯 在 水 作用下， 以 乙醇 为溶剂， 生成 1-p-methoxyphenyl-2,2-dimethylvinyl cation
  参考文献：
  名称：

  为什么乙烯基阳离子是缓慢的亲电试剂？

  摘要：

  乙烯基阳离子 2 [Ph2C=C+-(4-MeO-C6H4)] 和 3 [Me2C=C+-(4-MeO-C6H4)]（由激光闪光光解产生）与多种亲核试剂（例如、吡咯、卤化物离子和含有不同量水或醇的溶剂）已通过光度法测定。发现亲核试剂对这些乙烯基阳离子的反应顺序与对二芳基碳鎓离子（二苯甲基鎓离子）的反应顺序相同。然而，乙烯基阳离子的反应速率受亲核试剂变化的影响仅是二苯甲基离子的反应速率的一半。因此，乙烯基阳离子和二苯甲基离子的相对反应性在很大程度上取决于亲核试剂的性质。结果表明，乙烯基阳离子 2 和 3 分别反应，使用三氟乙醇比母体二苯鎓离子 (Ph)2CH+ 慢 227 和 14 倍，即使在溶剂分解反应（25°C 时为 80% 乙醇水溶液）中，导致 2 和 3 的乙烯基溴离子化得更慢（半衰期 1.15年和 33 天）比 (Ph)2CH-Br（半衰期 23 秒）。通过高级 MO 计算研究了这

  DOI：

  10.1021/jacs.6b10889

文献信息

• Lifetimes and UV-visible absorption spectra of benzyl, phenethyl, and cumyl carbocations and corresponding vinyl cations. A laser flash photolysis study
  作者：Frances L Cozens、V M Kanagasabapathy、Robert A McClelland、Steen Steenken

  DOI：10.1139/v99-210

  日期：1999.12.5

  Benzyl (4-MeO, 4-Me, and 4-methoxy-1-naphthylmethyl), phenethyl (4-Me₂N, 4-MeO, 3,4-(MeO)₂, 4-Me, 3-Me, 4-F, 3-MeO, 2,6-Me₂, parent, and 4-methoxy-1-naphthylethyl) and cumyl (4-Me₂N, 4-MeO, 4-Me, parent) cations have been studied by laser flash photolysis (LFP) in 2,2,2-trifluoroethanol (TFE) and 1,1,1,3,3,3-hexafluoroisopropanol (HFIP). In most cases styrene or α-methylstyrene precursors were employed for the phenethyl and cumyl ions, the intermediate being obtained by solvent protonation of the excited state. Benzyl cations were generated by photoheterolysis of trimethylammonium and chloride precursors. While a 4-MeO substituent provides sufficient stabilization to permit observation of cations in TFE, cations with less stabilizing substituents usually require the less nucleophilic HFIP. Even in this solvent, the parent benzyl cation is too short-lived (lifetime <20 ns) to be observed. When generated in HFIP, phenethyl cations can be seen to react with unphotolyzed styrene, giving rise to dimer cations that are observed to grow in as the initial phenethyl cation decays. The dimer cations, in common with the oligomer cations seen in cationic styrene polymerization, have a λ_max 15-20 nm higher than the monomer and react with both solvent and styrene several orders of magnitude more slowly. This stabilization relative to the phenethyl may reflect an interaction with the aryl group present at the gamma-carbon. Cations 4-MeOC₆H₄C⁺(R)-CH₃ (R = Me, Et, i-Pr, t-Bu, cyclopropyl, C₆H₅, 4-MeOC₆H₄) were generated in TFE via the photoprotonation route. The alkyl series shows that steric effects are important in the decay reaction. The cation with R = cyclopropyl is a factor of 1.5 less reactive than the cation where R = phenyl. Several vinyl cations have also been generated by photoprotonation of phenylacetylenes. ArC⁺=CH₂ has a reactivity very similar to that of its analog ArC⁺H-CH₃, the vinyl cation being slightly (factors of 2-5) shorter-lived. For the various series of cations, including vinyl, substituents in the aryl ring have a consistent effect on the λ_max, a shift to higher wavelength relative to hydrogen of 15 nm for 4-Me, 30 nm for 4-MeO, and 50 nm for 4-Me₂N.Key words: photogenerated carbocations, carbocation lifetime, styrene, photoprotonation.

  苯甲基（4-MeO，4-Me和4-甲氧基-1-萘基甲基）、苯乙基（4-Me2N，4-MeO，3,4-(MeO)2，4-Me，3-Me，4-F，3-MeO，2,6-Me2，母体和4-甲氧基-1-萘基乙基）和叔丁基（4-Me2N，4-MeO，4-Me，母体）阳离子在2,2,2-三氟乙醇（TFE）和1,1,1,3,3,3-六氟异丙醇（HFIP）中通过激光闪光光解（LFP）进行了研究。在大多数情况下，苯乙烯或α-甲基苯乙烯前体被用于苯乙基和叔丁基离子，中间体通过溶剂质子化激发态而获得。苯甲基阳离子是通过三甲基铵和氯化物前体的光异裂生成的。虽然4-MeO取代基提供了足够的稳定性以在TFE中观察到阳离子，但具有较少稳定取代基的阳离子通常需要较不亲核的HFIP。即使在这种溶剂中，母体苯甲基阳离子也太短寿命（寿命<20 ns）而无法观察到。在HFIP中生成的苯乙基阳离子可以看到与未经光解的苯乙烯反应，导致观察到的二聚体阳离子在初始苯乙基阳离子衰减时增长。与阳离子苯乙烯聚合中观察到的寡聚体阳离子一样，二聚体阳离子的λmax比单体高15-20 nm，并且与溶剂和苯乙烯反应速度慢几个数量级。相对于苯乙基的这种稳定性可能反映了与伽马碳上存在的芳基的相互作用。在TFE中通过光质子化途径生成了4-MeOC6H4C+(R)-CH3（R = Me，Et，i-Pr，t-Bu，环丙基，C6H5，4-MeOC6H4）阳离子。烷基系列表明立体效应在衰减反应中很重要。当R = 环丙基时，其反应性比R = 苯基的阳离子少1.5倍。还通过对苯乙炔的光质子化生成了几种乙烯阳离子。ArC+=CH2的反应性与其类似物ArC+H- 非常相似，乙烯阳离子寿命略短（2-5倍因子）。对于包括乙烯在内的各系列阳离子，芳香环中的取代基对λmax有一致的影响，相对于氢的15 nm的4-Me，30 nm的4-MeO和50 nm的4-Me2N的波长偏移。关键词：光产生的碳正离子，碳正离子寿命，苯乙烯，光质子化。
• Photochemical Formation and Electrophilic Reactivities of Vinyl Cations. Influence of Substituents, Anionic Leaving Groups, Solvents, and Excitation Wavelength on Photoheterolysis and Photohomolysis of 1-(p-R-Phenyl)-2-(2,2'-biphenyldiyl)vinyl Halides
  作者：Jan-Maarten Verbeek、Marion Stapper、Erik S. Krijnen、Jan-Dirk van Loon、Gerrit Lodder、Steen Steenken

  DOI：10.1021/j100089a027

  日期：1994.9

  Using product analysis and time-resolved laser flash photolysis techniques, the photochemistry at lambda(exc) approximate to 250 and 310 nm (exe = excitation) of 1-(p-R-phenyl)-2-(2,2'-biphenyldiyl)vinyl halides (R = H, Me, MeO) in methanol and acetonitrile at room temperature was studied. The title compounds undergo photoheterolysis and photohomolysis to give vinyl cations =C+- (carbenium ions) and vinyl radicals =C-.-. The cation: radical ratio increases with electron-donating strength of the substituent R, H < Me < MeO, and with anionic leaving group power of the halide, F- < Cl- < Br- < I-, indicating that the cleavage of the C-X bond to yield cation and halide anion proceeds, in the rate-determining step, by heterolysis and not by homolysis followed by electron transfer in the radical pair. The cation:radical ratio is solvent dependent: e.g., for the vinyl bromide with R = MeO and with lambda(exc) = 308 nm, in CH2Cl2 as solvent, only radical is observed, in comparison with only cation in the much more polar solvent acetonitrile. In acetonitrile-methanol mixtures, the absolute yields of both cation and radical go through a maximum as the methanol content is increased, however, the cation:radical ratio decreases continuously with increasing [MeOH]. For a particular R, the quantum yield for C-X bond cleavage is higher at approximate to 250 than at approximate to 310 nm. Also, the cation:radical ratio is wavelength-dependent: at lambda(exc) approximate to 310 nm there is relatively more heterolysis than at lambda(exc),,, x 250 nm. Rate constants for reaction of the cations with nucleophiles were determined in acetonitrile. Those for reaction of the cation with R = MeO (lifetime in acetonitrile 7 ys) with anionic nucleophiles such as the halides are at the diffusion limit in this solvent, approximate to 2 x 10(10) M(-1) s(-1), whereas those for reaction with water, alcohols, and cyclic ethers are of the order 10(5)-10(6) M(-1) s(-1). The less stabilized cation (R = Me) reacts with alcohols faster by the factor approximate to 100, and it decays in acetonitrile approximate to 100 times more rapidly. Also, 1-(p-a-phenyl)-2-dimethylvinyl bromides (R = H, Me, MeO) were photolyzed in acetonitrile. In the case of R = MeO, the cation p-CH3O-C6H4-C+=CMe(2) was seen (lifetime 770 ns), and its reactivity with alcohols (k values of 10(6)-10(7) M(-1) s(-1)) and halides (k values of 10(10) M(-1) s(-1)) was determined. The vinyl radicals =C-.- react with O-2 to yield vinylperoxyl radicals =C-O-2(.) which have absorption maxima at approximate to 390 nm.
• Kobayashi, Shinjiro; Zhu, Qin Qin; Schnabel, Wolfram, Zeitschrift fur Naturforschung, B: Chemical Sciences, 1988, vol. 43, # 7, p. 825 - 829
  作者：Kobayashi, Shinjiro、Zhu, Qin Qin、Schnabel, Wolfram

  DOI：——

  日期：——