4-methoxycumyl cation | 22666-71-3

• 分子结构分类: 有机化合物 - 有机氧化合物
• 英文名称: 4-methoxycumyl cation
• 英文别名: 1-(4'-Methoxyphenyl)-1-methyl-ethyl-kation；p-Methoxy-phenyl-dimethyl-carboniumion；p-Methoxy-i-propylbenzol-Kation；Methyl-(4-propan-2-ylidenecyclohexa-2,5-dien-1-ylidene)oxidanium
• CAS: 22666-71-3
• 化学式: C₁₀H₁₃O
• 分子量: 149.213
• InChiKey: AZBKRYQVGMETKH-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2
• 重原子数：
  11
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.3
• 拓扑面积：
  1
• 氢给体数：
  0
• 氢受体数：
  0

反应信息

• 作为反应物：
  描述：

  4-methoxycumyl cation 在 sodium azide 作用下， 以 水 为溶剂， 生成 2-(4-甲氧基苯基)丙-2-醇 、 1-(2-azidopropan-2-yl)-4-methoxybenzene
  参考文献：
  名称：

  The effects of .alpha.-substituents on the kinetic and thermodynamic stability of 4-methoxybenzyl carbocations: carbocation lifetimes that are independent of their thermodynamic stability

  摘要：

  The following new rate constants for reaction of alpha-substituted 4-methoxybenzyl carbocations, 4-MeOC6H4CR1(R2)+, With a solvent of 50:50 (v/v) trifluoroethanol/water at 25-degrees-C and ionic strength 0.50 (NaClO4) are reported: 4-MeOC6H4CH(OMe)+, k(S) = 2.2 X 10(7) s-1; 4-MeOC6H4CH(N3)+, k(S) = 3.3 X 10(5) s-1; 4-MeOC6H4C(CH3)2+, k(S) = 1.3 x 10(7) s-1; 4-MeOC6H4CH(CO2Et)+, k(S) = 1.4 X 10(7) s-1; 4-MeOC6H4CCH3(CF3)+, k(S) = 2.5 x 10(7) s-1. The values of k(S) for reaction of 4-MeOC6H4CR1(R2)+ with 50:50 (v/v) trifluoroethanol/water are nearly independent of very large changes in the thermodynamic stability of these carbocations caused by the addition of a wide range of electron-withdrawing or electron-donating groups at the alpha-position. In the most extreme case, the change from an alpha-methoxy to two alpha-(trifluoromethyl) substituents leads to a 23 kcal/mol thermodynamic destabilization of 4-MeOCrH4CR1(R2)+ relative to the neutral azide ion adducts but a 5-fold decrease in its reactivity toward solvent. The data show that the effects of alpha-substituents on the kinetic stability of 4-MeOC6H4CR1(R2)+ are complex and do not parallel the thermodynamic stability of these carbocations. The results are explained by consideration of the polar and resonance effects of the alpha-substituents on both the thermodynamic driving force and the intrinsic barrier for capture of the carbocations by solvent. These reactions are a new example of the consequences of the ''principle of nonperfect synchronization''.41

  DOI：

  10.1021/jo00074a036
• 作为产物：
  描述：

  1-异丙烯基-4-甲氧基苯 在 2,2,2-三氟乙醇 作用下， 生成 4-methoxycumyl cation
  参考文献：
  名称：

  Lifetimes and UV-visible absorption spectra of benzyl, phenethyl, and cumyl carbocations and corresponding vinyl cations. A laser flash photolysis study

  摘要：

  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-CH3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。

  DOI：

  10.1139/v99-210

文献信息

• Deuterium isotope effects on the carbon-13 chemical shifts in 2-substituted 2-norbornyl cations
  作者：Kenneth L. Servis、Robert L. Domenick、David A. Forsyth、Yi Pan

  DOI：10.1021/ja00258a003

  日期：1987.11

  Deuterium isotope effects on /sup 13/C chemical shifts have been examined as a function of location of deuterium in the C/sub 3/-exo or C/sub 3/-endo positions and as a function of increasing electron demand in the series 2-norbornanone, 2-aryl-2-nonbornyl cations, and 2-methyl-2-norbornyl cation. Comparison with isotope shifts in 2-aryl-2-propyl cations demonstrates a change in the type of response

  已检查氘同位素对 /sup 13/C 化学位移的影响，作为氘在 C/sub 3/-exo 或 C/sub 3/-endo 位置的函数以及系列中电子需求增加的函数2-降冰片酮、2-芳基-2-壬基阳离子和2-甲基-2-降冰片基阳离子。与 2-芳基-2-丙基阳离子中同位素位移的比较表明，随着电子需求的增加，对 2-芳基-2-降冰片基阳离子中同位素扰动的响应类型发生了变化。随着电子需求的增加，结果与 sigma 桥接的开始一致。在阳离子中心观察到的同位素位移被认为是由于西格玛框架的扰动（感应型扰动）引起的小高场位移的贡献，由于超共轭的扰动引起的低场位移，以及来自三中心双电子键合扰动的潜在大的高场偏移。由于同位素效应的振动起源，NMR 同位素位移可能是西格玛桥联的特别敏感的探针。
• 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-CH3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。
• Substituent Effect on the Stability of Benzyl Cation in the Gas Phase
  作者：Masaaki Mishima、Kiyoshi Arima、Satoshi Usui、Mizue Fujio、Yuho Tsuno

  DOI：10.1246/cl.1987.1047

  日期：1987.6.5

  Chloride ion affinities of substituted benzyl cations in the gas phase have been determined by means of an ICR mass spectrometer. The substituent effect has been analyzed in terms of the LArSR Eq., giving a ρ=13.6 and an r+=1.31.

  气相中取代的苄基阳离子的氯离子亲和力已通过ICR质谱仪测定。已根据 LArSR 方程分析取代基效应，得出 ρ=13.6 和 r+=1.31。
• Absolute Reactivity of the 4-Methoxycumyl Cation in Non-Acid Zeolites
  作者：Melanie A. O'Neill、Frances L. Cozens、Norman P. Schepp

  DOI：10.1021/ja993619d

  日期：2000.6.1

  The reactivity of the 4-methoxycumyl cation in a series of alkali metal cation-exchanged zeolites (LiY, NaY, KY, RbY CsY, NaX, NaMor, and Naβ) in the absence and presence of coadsorbed alcohols and water is examined using nanosecond laser flash photolysis. In dry zeolites, the absolute reactivity of the carbocation is found to be strongly dependent on the nature of the alkali counterion, the Si/Al

  4-甲氧基枯基阳离子在一系列碱金属阳离子交换沸石（LiY、NaY、KY、RbY CsY、NaX、NaMor 和 Naβ）中在共吸附醇和水不存在和存在的情况下的反应性使用纳秒激光检查闪光光解。在干沸石中，碳正离子的绝对反应性强烈依赖于碱反离子的性质、Si/Al 比和骨架形态，碳正离子在 Naβ 中的寿命几乎是 10000 倍。在 CsY。结果表明，碳正离子衰变机制涉及沸石骨架作为亲核试剂的直接参与，导致产生骨架结合的烷氧基物质。
• Direct Observation of Cumyl Cations in Nonacidic Zeolites. Absolute Lifetime and Reactivity with Coabsorbed Alcohols
  作者：Frances L. Cozens、Melanie O'Neil、Norman P. Schepp

  DOI：10.1021/ja970690f

  日期：1997.8.1