4,5-二甲基-2,3-二氢呋喃 | 1487-16-7

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 二氢呋喃
• 中文名称: 4,5-二甲基-2,3-二氢呋喃
• 英文名称: 2,3-dimethyl-4,5-dihydrofuran
• 英文别名: 4,5-dimethyl-2,3-dihydrofuran
• CAS: 1487-16-7
• 化学式: C₆H₁₀O
• 分子量: 98.1448
• InChiKey: JKHBEWLCMFXCFW-UHFFFAOYSA-N

计算性质

• 辛醇/水分配系数(LogP)：
  1.1
• 重原子数：
  7
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.67
• 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：

  4,5-二甲基-2,3-二氢呋喃 在 蒽醌-2,6-二磺酸钠 作用下， 以 水 为溶剂， 生成
  参考文献：
  名称：

  水溶液中三重态敏化电子转移形成二氢呋喃自由基的傅里叶变换EPR研究及量子化学计算

  摘要：

  从 2,3-二氢呋喃、2-甲基-4,5-二氢呋喃和 2,3-二甲基-4,5-二氢呋喃到激光诱导的蒽醌-2,6-二磺酸三重态电子转移形成的自由基为通过傅里叶变换电子顺磁共振（FT EPR）在纳秒时间尺度在水溶液中研究。使用 2,3-二甲基-4,5-二氢呋喃和 2-甲基-4,5-二氢呋喃作为电子供体，直接观察到自由基阳离子，而使用 2,3-二氢呋喃作为电子供体，观察到的自由基是自由基阳离子。自由基结构的分配是通过模拟实验 EPR 光谱完成的，并得到量子化学密度泛函理论 (DFT) 计算的支持。在使用 2-methyl-4 的实验中，5-二氢呋喃只有一个 OH--加合物可以被确定，尽管其他未知的自由基对测量的光谱有贡献。使用 2,3-二氢呋喃，检测到两个 OH--加合物自由基和去质子化自由基阳离子以及来自二聚自由基的贡献。分别测定了电子转移到蒽醌-2,6-二磺酸盐三联体的速率常数和从主要的 2,

  DOI：

  10.1039/b109064j
• 作为产物：
  描述：

  5-hydroxy-3-methyl-2-pentanone 在 磷酸 作用下， 以50%的产率得到4,5-二甲基-2,3-二氢呋喃
  参考文献：
  名称：

  Dye-sensitized photooxygenation of 2,3-dihydrofurans: competing [2 + 2] cycloadditions and ene reactions of singlet oxygen with a rigid cyclic enol ether system

  摘要：

  Singlet oxygen reacts with 2,3-dihydrofuran (1), 5-methyl- (7), 4,5-dimethyl- (13), and 4-carbomethoxy-5-methyl-2,3-dihydrofuran (20), 5,6-dimethyl-3,4-dihydro-2H-pyran (26), and 3-methoxy-2-methyl-2-butene (32) in nonpolar and polar aprotic solvents to yield dioxetanes and allylic hydroperoxides, except 32, which gives only allylic hydroperoxides. The dioxetanes were isolated, but decompose slowly with weak chemiluminescence at room temperature to yield the corresponding dicarbonyl compounds. The allylic hydroperoxides produced by the cyclic enol ethers could not be isolated or separated by high vacuum distillation or by chromatography; the endocyclic allylic hydroperoxides arising from the dihydrofurans eliminate H2O2 to yield the corresponding furans while the exocyclic allylic hydroperoxides give unknown products. Allylic hydroperoxides 28 and 29 and the dioxetane 27 obtained from 26 yield the same dicarbonyl compound 31. The proportion of dioxetanes to allylic hydroperoxides depends on ring size and substitution of the enol ethers and on solvent polarity. Smaller ring size, greater electron-donor substitution, and solvent polarity favor the formation of dioxetanes at the expense of allylic hydroperoxides. It is noteworthy that enol ether 20, an alpha,beta-unsaturated ester, forms appreciable amounts of a dioxetane in polar solvents (44% in acetonitrile). Kinetic results show that the rate and product distribution of the ene reaction are independent of solvent polarity, whereas the rate of dioxetane formation increases with solvent polarity. It is suggested that [2 + 2] cycloadditions and ene reactions occur via different transition states and intermediates, zwitterions and perepoxides, respectively. Furthermore, the remarkable propensity to dioxetane formation of dihydrofurans compared to that of dihydropyrans and the other enol ethers seems to be due to the rigidity of the five-membered ring in the transition state and intermediate zwitterion.

  DOI：

  10.1021/jo00012a040

文献信息

• Alcohol Synthesis by Cobalt-Catalyzed Visible-Light-Driven Reductive Hydroformylation
  作者：Connor S. MacNeil、Lauren N. Mendelsohn、Tyler P. Pabst、Gabriele Hierlmeier、Paul J. Chirik

  DOI：10.1021/jacs.2c07745

  日期：2022.10.26

  A cobalt-catalyzed reductive hydroformylation of terminal and 1,1-disubstituted alkenes is described. One-carbon homologated alcohols were synthesized directly from CO and H2, affording anti-Markovnikov products (34–87% yield) with exclusive regiocontrol (linear/branch >99:1) for minimally functionalized alkenes. Irradiation of the air-stable cobalt hydride, (dcype)Co(CO)2H (dcype = dicyclohexylphosphinoethane)

  描述了钴催化的末端和 1,1-二取代烯烃的还原加氢甲酰化。一碳同系醇直接从 CO 和 H 2合成，提供抗马尔可夫尼科夫产品（34-87% 产率），对最小功能化烯烃具有独特的区域控制（线性/支链 >99:1）。用蓝光照射空气稳定的氢化钴 (dcype)Co(CO) 2 H（dcype = 二环己基膦基乙烷）产生了介导烯烃加氢甲酰化和随后的醛氢化的活性催化剂。通过使用合成气混合物的多核 NMR 光谱对串联催化反应进行原位监测，研究了绝对区域控制的机理起源。
• 1,2-Dioxetanes derived from 4,5-dimethyl-2,3-dihydrofuran and 4,5-dimethyl-2,3-dihydrothiophene. Synthesis via photooxygenation, activation parameters, and excitation properties
  作者：Waldemar Adam、Axel G. Griesbeck、Klaus Gollnick、Karen Knutzen-Mies

  DOI：10.1021/jo00242a028

  日期：1988.4
• GOLLNICK, KLAUS;KNUTZEN-MIES, KAREN, J. ORG. CHEM., 56,(1991) N2, C. 4017-4027
  作者：GOLLNICK, KLAUS、KNUTZEN-MIES, KAREN

  DOI：——

  日期：——
• ADAM, WALDEMAR;GRIESBECK, AXEL G.;GOLLNICK, KLAUS;KNUTZEN-MIES, KAREN, J. ORG. CHEM., 53,(1988) N 7, 1492-1495
  作者：ADAM, WALDEMAR、GRIESBECK, AXEL G.、GOLLNICK, KLAUS、KNUTZEN-MIES, KAREN

  DOI：——

  日期：——
• Dye-sensitized photooxygenation of 2,3-dihydrofurans: competing [2 + 2] cycloadditions and ene reactions of singlet oxygen with a rigid cyclic enol ether system
  作者：Klaus Gollnick、Karen Knutzen-Mies

  DOI：10.1021/jo00012a040

  日期：1991.6

  Singlet oxygen reacts with 2,3-dihydrofuran (1), 5-methyl- (7), 4,5-dimethyl- (13), and 4-carbomethoxy-5-methyl-2,3-dihydrofuran (20), 5,6-dimethyl-3,4-dihydro-2H-pyran (26), and 3-methoxy-2-methyl-2-butene (32) in nonpolar and polar aprotic solvents to yield dioxetanes and allylic hydroperoxides, except 32, which gives only allylic hydroperoxides. The dioxetanes were isolated, but decompose slowly with weak chemiluminescence at room temperature to yield the corresponding dicarbonyl compounds. The allylic hydroperoxides produced by the cyclic enol ethers could not be isolated or separated by high vacuum distillation or by chromatography; the endocyclic allylic hydroperoxides arising from the dihydrofurans eliminate H2O2 to yield the corresponding furans while the exocyclic allylic hydroperoxides give unknown products. Allylic hydroperoxides 28 and 29 and the dioxetane 27 obtained from 26 yield the same dicarbonyl compound 31. The proportion of dioxetanes to allylic hydroperoxides depends on ring size and substitution of the enol ethers and on solvent polarity. Smaller ring size, greater electron-donor substitution, and solvent polarity favor the formation of dioxetanes at the expense of allylic hydroperoxides. It is noteworthy that enol ether 20, an alpha,beta-unsaturated ester, forms appreciable amounts of a dioxetane in polar solvents (44% in acetonitrile). Kinetic results show that the rate and product distribution of the ene reaction are independent of solvent polarity, whereas the rate of dioxetane formation increases with solvent polarity. It is suggested that [2 + 2] cycloadditions and ene reactions occur via different transition states and intermediates, zwitterions and perepoxides, respectively. Furthermore, the remarkable propensity to dioxetane formation of dihydrofurans compared to that of dihydropyrans and the other enol ethers seems to be due to the rigidity of the five-membered ring in the transition state and intermediate zwitterion.