(α,β,β,β)-1-anisyl-2-methyl-3,4-dicyanocyclobutane

• 分子结构分类: 有机化合物 - 苯类化合物 - 苯酚醚
• 英文名称: (α,β,β,β)-1-anisyl-2-methyl-3,4-dicyanocyclobutane
• 英文别名: (1R,2S,3R,4R)-3-(4-methoxyphenyl)-4-methylcyclobutane-1,2-dicarbonitrile
• 化学式: C₁₄H₁₄N₂O
• 分子量: 226.278
• InChiKey: JPSBGCARMLIQKV-VKKKGTNTSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  2
• 重原子数：
  17
• 可旋转键数：
  2
• 环数：
  2.0
• sp3杂化的碳原子比例：
  0.43
• 拓扑面积：
  56.8
• 氢给体数：
  0
• 氢受体数：
  3

反应信息

• 作为产物：
  描述：

  茴香烯 、 反丁烯二腈 在 9-氰基蒽 作用下， 以 乙腈 为溶剂， 生成 (α,β,α,α)-1-anisyl-2-methyl-3,4-dicyanocyclobutane 、 (α,β,β,α)-1-anisyl-2-methyl-3,4-dicyanocyclobutane 、 (α,β,α,β)-1-anisyl-2-methyl-3,4-dicyanocyclobutane 、 (α,β,β,β)-1-anisyl-2-methyl-3,4-dicyanocyclobutane
  参考文献：
  名称：

  Photoinduced Electron Transfer Reactions of Aryl Olefins. 2. Cis−Trans Isomerization and Cycloadduct Formation in Anethole−Fumaronitrile Systems in Polar Solvents

  摘要：

  In acetonitrile, the photoreactions of cis-anethole, cA, or trans-anethole, tA, with fumarodinitrile, FN, lead to isomerization of both substrate and quencher and to mixed [2 + 2] cycloaddition. By NMR analysis and by NOE measurements it was shown that the same four stereoisomers of 1-anisyl-2-methyl-3,4-dicyanocyclobutane are formed in equal yields regardless of whether the substrate is cA or tA. The configuration of the anethole-derived moiety in these adducts is always trans, whereas all possible configurations of the cyano groups occur, From Stern-Volmer experiments it was concluded that the quenching mechanism is electron transfer, not exciplex formation. Electron-transfer quenching is also the pathway leading to the cycloadducts, as was established by photoinduced electron-transfer sensitization. These photoreactions give rise to strong nuclear spin polarizations (CIDNP) in the starting and isomerized forms of both substrate and quencher as well as in the cycloadducts. Radical pairs A(.+)FN(.-) (RP I) consisting of the radical cation of the anethole and the radical anion of fumarodinitrile were identified as the predominant source of the polarizations. The starting materials are regenerated by back electron transfer of singlet pairs; likewise, back electron transfer of triplet pairs (3)RP I to give either triplet anethole, (3)A, or triplet fumarodinitrile, (FN)-F-3, occurs and constitutes the main pathway to isomerization of substrate and quencher. The cycloadducts are also formed via (3)RP I; a significant participation of free radicals in their generation was ruled out. The stereochemistry of the products and the different ratios of polarization intensities of the isomerized olefin and the cycloadducts can only be explained by the intermediacy of a triplet biradical (3)BR. After intersystem crossing to the singlet state, ring closure of (1)BR competes with biradical scission. The latter process provides an additional isomerization pathway, which differs from the pathway via triplet olefins by leading only to one-way cis-trans isomerization of the substrate. (3)BR is formed by geminate combination of triplet radical ion pairs (3)RP I; an indirect pathway via back electron transfer of (3)RP I to give 3A or 3FN followed by attack to the other olefin, as has been proposed for similar photocycloadditions, could be excluded unambiguously. Despite the different precursor multiplicity, the mechanism of the [2 + 2] photocycloaddition of donor and acceptor olefins investigated in this work is thus identical to the mechanism of the Paterno-Buchi reaction between donor olefins and electron-deficient carbonyl compounds which we recently reported. The CIDNP experiments at variable quencher concentration revealed the presence of an additional radical pair RP II, also containing A(.+) but an anion other than FN.-. It was shown that RP II results from a biphotonic process. These findings were explained by two-photon ionization of the anethole and formation of an oligomeric anion of acetonitrile.

  DOI：

  10.1021/ja9511578