3,4-dimethyl-5,6-dihydro-2H-pyran-2-one | 57668-96-9

• 分子结构分类: 有机化合物 - 有机杂环化合物 - 吡喃
• 英文名称: 3,4-dimethyl-5,6-dihydro-2H-pyran-2-one
• 英文别名: 5,6-Dihydro-2,3-dimethyl-2H-pyran-2-one；3,4-dimethyl-5,6-dihydro-pyran-2-one；4,5-dimethyl-2,3-dihydropyran-6-one
• CAS: 57668-96-9
• 化学式: C₇H₁₀O₂
• 分子量: 126.155
• InChiKey: ZJBVHUCUCCHKFH-UHFFFAOYSA-N

物化性质

• 沸点：
  241.0±19.0 °C(Predicted)
• 密度：
  1.023±0.06 g/cm3(Predicted)

计算性质

• 辛醇/水分配系数(LogP)：
  1
• 重原子数：
  9
• 可旋转键数：
  0
• 环数：
  1.0
• sp3杂化的碳原子比例：
  0.57
• 拓扑面积：
  26.3
• 氢给体数：
  0
• 氢受体数：
  2

反应信息

• 作为反应物：
  描述：

  3,4-dimethyl-5,6-dihydro-2H-pyran-2-one 在 4-二甲氨基吡啶 、 manganese(IV) oxide 、 氢氧化钾 、 lithium aluminium tetrahydride 、 正丁基锂 、 三苯基甲烷 、 三乙胺 作用下， 以 四氢呋喃 、 正己烷 、 二氯甲烷 为溶剂， 反应 52.42h， 生成 (Z)-7-[tert-butyl(dimethyl)silyl]oxy-4,5-dimethylhept-4-en-1-yn-3-ol
  参考文献：
  名称：

  Enynones in Organic Synthesis. 7. Substituent Effects on the .alpha.-Tocopherol-Catalyzed Cyclization of Enynones to Methylenecyclopentenones. Convenient Syntheses of Members of the Methylenomycin Class of Antibiotics

  摘要：

  Substituent effects on the a-tocopherol (vitamin E, 3b) catalyzed cyclization of a wide variety of enynones 1a-z to methylenecyclopentenones 7a-z have been examined, with particular emphasis given to electron-withdrawing and -donating groups at positions 2-4 and 6. In general, electron-withdrawing groups at positions 4 and 6 dramatically accelerate the cyclization process, while strong electron-donating groups at positions 3 and 4 completely inhibit reaction. Relatively little effect is exerted by groups at C-2, except for the methyl ester derivative 1i, which is totally unreactive. This methodology was employed in the syntheses of the methylenecyclopentenone antibiotics methylenomycin B (7a) and desepoxy-4,5-didehydromethylenomycin A (7z) and in formal syntheses of methylenomycin A (8) and xanthocidin (9).

  DOI：

  10.1021/jo00097a036
• 作为产物：
  描述：

  2-methyl-acrylic acid 3-methyl-but-3-enyl ester 在 C₄₉H₅₄Cl₂N₈O₈Ru 作用下， 以 甲苯 为溶剂， 反应 3.0h， 以20%的产率得到3,4-dimethyl-5,6-dihydro-2H-pyran-2-one
  参考文献：
  名称：

  [（NHC）（NHCEWG）RuCl2（CHPh）]络合物通过闭合环复分解有效形成位阻烯烃

  摘要：

  用于RCM的具有EWG的NHC：具有两个N-杂环卡宾（NHC）的钌配合物（其中一个被吸电子基团（EWG）取代）是高效的（预）催化剂，可通过环戊烯合成四取代的烯烃和三取代的烯烃封闭复分解反应（RCM，请参阅方案）。

  DOI：

  10.1002/anie.200900935

文献信息

• Microwave-Assisted Ruthenium-Catalysed Olefin Metathesis in Fluorinated Aromatic Hydrocarbons: A Beneficial Combination
  作者：Cezary Samojłowicz、Etienne Borré、Marc Mauduit、Karol Grela

  DOI：10.1002/adsc.201100053

  日期：2011.8

  High conversions in ruthenium-based olefin metathesis of demanding substrates are commonly forced by using a high loading of a catalyst and conducting reactions at elevated temperature for extended times. However, in many cases this approach is not fully effective. In this article we present that fluorinated aromatic hydrocarbons (FAH) combined with microwave (MW) irradiation using a commercially available

  苛刻的底物在钌基烯烃复分解反应中的高转化率通常是通过使用大量催化剂并在高温下长时间进行反应来强制实现的。但是，在许多情况下，这种方法并不完全有效。在本文中，我们介绍了使用可商购的钌基预催化剂与微波（MW）辐射相结合的氟化芳烃（FAH）为吸引人的烯烃复分解转化创造了诱人的反应条件。
• Facile synthesis of [(NHC)(NHCewg)RuCl2(CHPh)] complexes
  作者：Stefanie Wolf、Herbert Plenio

  DOI：10.1016/j.jorganchem.2010.07.014

  日期：2010.10

  The utility of [(NHC)(PPh3)RuCl2(CHPh)] for the facile and efficient synthesis of ten complexes of the type [(NHC)(NHCewg)RuCl2(CHR)] with saturated and unsaturated NHC ligands in 85–94% isolated yield via a simple one step synthesis utilizing [AgI(NHCewg)] as NHCewg transfer reagents was demonstrated.

  [（NHC）（PPh 3）RuCl 2（CHPh）]用于轻松高效地合成10种[（NHC）（NHC ewg）RuCl 2（CHR）]与饱和和不饱和NHC配体的配合物通过简单的一步合成，利用[AgI（NHC ewg）]作为NHC ewg转移试剂，分离出的产率为85-94％。
• An [(NHC)(NHC_EWG)RuCl₂(CHPh)] Complex for the Efficient Formation of Sterically Hindered Olefins by Ring-Closing Metathesis
  作者：Tim Vorfalt、Steffen Leuthäußer、Herbert Plenio

  DOI：10.1002/anie.200900935

  日期：2009.6.29

  NHC with EWGs for RCM: Ruthenium complexes with two N‐heterocyclic carbenes (NHCs), one of them substituted with electron‐withdrawing groups (EWGs), are highly efficient (pre)catalysts for the synthesis of tetrasubstituted olefins and trisubstituted olefins by ring‐closing metathesis reactions (RCM, see scheme).

  用于RCM的具有EWG的NHC：具有两个N-杂环卡宾（NHC）的钌配合物（其中一个被吸电子基团（EWG）取代）是高效的（预）催化剂，可通过环戊烯合成四取代的烯烃和三取代的烯烃封闭复分解反应（RCM，请参阅方案）。
• Ruthenium Carbene Complexes with <i>N</i>,<i>N</i>‘-Bis(mesityl)imidazol-2-ylidene Ligands:  RCM Catalysts of Extended Scope
  作者：Alois Fürstner、Oliver R. Thiel、Lutz Ackermann、Hans-Jörg Schanz、Steven P. Nolan

  DOI：10.1021/jo9918504

  日期：2000.4.1

  The ruthenium carbene complexes 3a,b bearing imidazol-2-ylidene ligands constitute excellent precatalysts for ring-closing metathesis (RCM) reactions allowing the formation of tri- and tetrasubstituted cycloalkenes. They also apply to annulations that are beyond the scope of the standard Grubbs carbene 1 as well as to ring-closing reactions of acrylic acid derivatives even if the resulting alpha,beta-unsaturated lactones (or lactams) are tri- or tetrasubstituted. The reactivity of 3a was found to be highly dependent on the reaction medium: particularly high reaction rates are observed in toluene, although this solvent also leads to an increased tendency of the catalyst to isomerize the double bonds of the substrates.
• Synthesis of Alkyl-Substituted Six-Membered Lactones through Ring-Closing Metathesis of Homoallyl Acrylates. An Easy Route to Pyran-2-ones, Constituents of Tobacco Flavor
  作者：Andrea D'Annibale、Laura Ciaralli、Mauro Bassetti、Chiara Pasquini

  DOI：10.1021/jo070600h

  日期：2007.8.1

  The ring-closing metathesis (RCM) reactions of homoallylic acrylates bearing alkyl substituents on various positions of their skeleton afford the corresponding pentenolides in the presence of carbene ruthenium catalysts. For R-3 = R-4 = H, or R-3 = Me, R-4 = H, the reactions are catalyzed by complex [RuCl2(PCy3)(2)(CHPh)], while a second-generation Grubbs catalyst is required when R-3 = H and R-4 = Me, R-3 = R-4 = Me, or R-3 = i-Pr and R-4 = H. Alkyl substitution at the homoallylic carbon (R-1, R-2) increases the yield of the reaction when both the acrylic and/or homoallylic double bonds are methyl-substituted. The interaction of the catalyst with the substrate in the initiation stage involves the homoallylic double bond rather than the acrylic moiety, and the resulting alkylidene species from the first-generation Grubbs catalyst can be observed by H-1 and P-31 NMR. The racemic tobacco constituents 4-isopropyl-5,6-dihydropyran-2-one and 4-isopropyltetrahydropyran-2-one are prepared via a short reaction sequence, involving the RCM reaction as the key transformation.