环酮及其衍生物的光化学反应研究进展

综述了环酮及其衍生物的光化学反应的有机进展.较详细地介绍了单环酮、芳香酮、二元酮和二元环酮的光氧化反应、光还原反应、光偶联反应,尤其是对非增感光氧化反应、潜手性酮的不对称光还原反应以及激光在有机光化学反应中的应用也进行了介绍.     

3-(2-喹啉基)酚酮的卤代和硝化反应

众所周知酚酮环可以进行多种亲电取代反应。我们曾研究过3—乙酰基酚酮、3—乙酰胺基酚酮和3—肉桂酰基酚酮的亲电取代反应。最近报道了喹啉基取代酚酮的合成,这些化合物分子中的酚酮环和喹     

五氧化二钒催化环己烯烯丙位氧化

 研究了以五氧化二钒为催化剂,以过氧化氢水溶液为氧源氧化环己烯. 考察了溶剂种类、溶剂用量、催化剂用量和反应温度等因素对催化剂性能的影响. 结果表明,常温下环己烯在此催化体系中主要发生烯丙位氧化反应生成环己烯酮. 溶剂的种类对催化活性和烯丙位酮式氧化的选择性具有较大的影响,丙酮是该反应的合适溶剂. 在丙酮与环己烯的体积比为4, 五氧化二钒与环己烯的质量比为1∶40, 过氧化氢与环己烯的摩尔比为3和反应温度为20 ℃的条件下,反应24 h后的环己烯转化率可达60%以上,环己烯酮选择性可达85%. 催化反应过程中丙酮可能与过氧化氢作用生成过氧化酮,从而进行氧转移,催化剂则经过V5+/V4+物种的循环使环己烯氧化成为环己烯酮等产物.     

离子液体中V2O5催化环己烯选择氧化合成 2-环己烯酮

研究了以V2O5为催化剂,H2O2为氧化剂,在室温离子液体中环己烯氧化制备2-环己烯酮的反应.考察了离子液体种类、反应温度、催化剂用量和氧化剂用量等因素对2-环己烯酮产率的影响.结果表明,在H2O2用量为110 mmol,V2O5/环己烯摩尔比为2%,反应温度为313 K的条件下,在[bmim]BF4离子液体中反应10 h后,环己烯的转化率和2-环己烯酮选择性分别为88.7%和91.1%.对含离子液体的催化体系的重复使用性能进行了考察.结果发现,随着使用次数的增加,环己烯的转化率以及2-环己烯酮的选择性有所下降.     

2-苯基/环己基取代环十二酮肟衍生物的合成及晶体结构

以环十二酮为原料,分别与溴代环己烷或苯基锂试剂反应制得2-环己基环十二酮和2-苯基环十二酮,还意外获得了副产物1,1'-二羟基-1,1'-联环十二烷.2-环己基环十二酮和2-苯基环十二酮与盐酸羟胺反应制备了2-环己基环十二酮肟和2-苯基环十二酮肟,与亚硝酸钠-盐酸体系反应获得了3-环己基-1,2-环十二二酮单肟和3-苯基-1,2-环十二二酮单肟.在溶液中结晶获得其中四个化合物单晶并进行了X射线衍射,结果表明1-苯基环十二醇和1,1'-二羟基-1,1'-联环十二烷在晶体中的十二元环均采取[3333]构象,两个取代基在角碳上;在晶体中2-环己基环十二酮肟的十二元环采取[3333]-2-酮构象,而3-苯基-1,2-环十二二酮单肟的十二元环则改变为[4233]-3,4-二酮构象,取代基均在边碳外向位,量子力学计算的结果与晶体衍射的结果一致.1,1'-二羟基-1,1'-联环十二烷在晶体中采取摞光盘一样完全重叠的自组装排列方式.     

8-羟基喹啉对V2O5催化氧化环己烯的调变作用

研究了8-羟基喹啉对丙酮中V2O5催化氧化环己烯合成环己烯酮的调变作用,考察了8-羟基喹啉的用量、反应温度、反应时间、溶剂和催化剂用量对环己烯氧化反应的影响,发现在该催化体系中生成的环己烯醇和环氧环己烷可转化成环己烯酮,在适当的反应条件下可抑制环己烯醇和环氧环己烷的生成.结果表明,当五氧化二钒的用量为1%,五氧化二钒与8-羟基喹啉之比为1∶2,在20℃以下反应时,过氧化氢几乎定向地将环己烯氧化成环己烯酮.认为是8-羟基喹啉与钒的配位作用促进了环己烯酮的生成.     

α-单取代-1,2-环十二二酮单肟的合成及晶体结构

通过α-单取代环十二酮与亚硝酰氯反应合成了一系列α-单取代-1,2-环十二二酮单肟,它们的结构经1H NMR,13C NMR,ESI-MS和元素分析确证.X射线衍射和量子力学计算结果表明,α-单取代环十二酮与亚硝酰氯反应生成α-单取代-1,2-环十二二酮单肟时,生成产物具有[4233]-3-酮和[3333]-2-酮两种...     

级联反应以及双环[2,2,2]辛烯酮的合成

研究了合成桥环化合物1的级联反应,不仅得到已知桥环化合物1,还得到了具有双环[2.2.2]辛烯酮的新桥环化合物2以及两个新的烯丙基取代的呫吨酮3和4。并对可能的反应机理进行了解释。     

(±)-麝香酮和(R)-麝香酮的自由基扩环合成法

以环十二酮为原料, 经自由基扩环反应, 合成(±)-麝香酮和(R)-麝香酮, 总收率分别为51%和32%。     

环氧树脂与氰酸酯共固化反应的研究

应用DSC、FT IR对乙酰丙酮过渡金属络合物催化促进的环氧树酯与氰酸酯共固化反应行为、历程以及固化物的结构特征进行了研究探讨 .结果表明 ,促进剂能够明显的降低固化反应温度 ,缩短固化反应时间 .反应历程首先是氰酸酯发生自聚反应形成二聚体或三聚体 (三嗪环 ) ,然后二聚体可进一步共聚形成三嗪环 ,此过程伴随着环氧基的聚醚反应 ,最后是三嗪环与剩余的环氧基反应形成唑烷酮 .在氰酸酯欠量的条件下 ,固化树脂中主要是唑烷酮和聚醚结构 ,三嗪环结构很少 ;在氰酸脂适量或过量条件下 ,固化树脂主要是三嗪环和唑烷酮结构 ,聚醚结构很少 .     

Acid‐Mediated Formation of Radicals or Baeyer–Villiger Oxidation from Criegee Adducts

The acid‐mediated reaction of ketones with hydroperoxides generates radicals, a process with reaction conditions similar to those of the Baeyer–Villiger oxidation but with an outcome resembling the formation of hydroxyl radicals via ozonolysis in the atmosphere. The Baeyer–Villiger oxidation forms esters from ketones, with the preferred use of peracids. In contrast, alkyl hydroperoxides and hydrogen peroxide react with ketones by condensation to form alkenyl peroxides, which rapidly undergo homolytic O? O bond cleavage to form radicals. Both reactions are believed to proceed via Criegee adducts, but the electronic nature of the peroxide residue determines the subsequent reaction pathways. DFT calculations and experimental results support the idea that, unlike previously assumed, the Baeyer–Villiger reaction is not intrinsically difficult with alkyl hydroperoxides and hydrogen peroxide but rather that the alternative radical formation is increasingly favored.     

Enzymatic kinetic resolution of racemic ketones catalyzed by Baeyer–Villiger monooxygenases

A set of racemic cyclic and linear ketones, as well as 2-phenylpropionaldehyde, were tested as substrates in the enzymatic Baeyer–Villiger oxidation catalyzed by two Baeyer–Villiger monooxygenases: phenylacetone monooxygenase (PAMO) and 4-hydroxyacetophenone monooxygenase (HAPMO). Excellent enantioselectivites (E > 200) can be obtained in the kinetic resolution processes depending on the substrate structure and the reaction conditions. The parameters affecting the biocatalytic properties of these enzymes were also studied, in order to establish a deeper understanding of these novel biocatalysts.     

A theoretical study on the mechanism of the baeyer–villiger type oxidation of 7‐phosphanorbornene 7‐Oxides

DFT computations have been performed on selected stationary points of the reaction path (reactants, intermediates, and products) of the Baeyer–Villiger type oxidation of 7‐phosphanorbornene 7‐oxide derivatives. Our computations justified the relevance of a Criegee‐type intermediate forming in the first step, analogously to the Baeyer–Villiger oxidation of ketones. The energy profile indicated a high‐energy barrier from the side of the products, supporting the kinetic character of the mechanism. The computations revealed that the mechanism does not include a previously assumed Berry‐pseudorotation step in the Criegee‐type intermediate. On the basis of the present results, we suggest that the regioselectivity of the Baeyer–Villiger type oxidation of the 7‐phosphanorbornene 7‐oxide derivatives may be determined by steric interactions between the leaving meta‐chlorobenzoate group and substituents on the 7‐phosphanorbornene skeleton in the Criegee‐type intermediate. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:759–766, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20366     

The role of the Baeyer–Villiger reaction in the liquid-phase oxidation of organic compounds

The data on the composition of ester products formed in the Baeyer–Villiger reaction in the liquid-phase oxidation of organic compounds with molecular oxygen, on production channel of peroxy acids, as well as on the influence of a carbonyl compound structure on its reactivity in reactions with peroxy acids have been classified and considered. The Baeyer–Villiger reaction was shown to be the main source of accessory primary alcohol esters and lactones in industrial processes of aerobic oxidation of cyclohexane and paraffin hydrocarbons.     

Nanoflow microreactor for dramatic increase not only in reactivity but also in selectivity: Baeyer–Villiger oxidation by aqueous hydrogen peroxide using lowest concentration of a fluorous lanthanide catalyst

Not only the reaction rate but also the regioselectivity in the scandium bis(perfluorooctanesulfonyl)amide-catalyzed Baeyer–Villiger reaction is remarkably increased by the development of the fluorous nanoflow microreactor system continuously controlled by the nanofeeder DiNaS (Direct Nanoflow System) even in the lowest concentration of the catalyst (≪0.1 mol%). The Baeyer–Villiger reaction completes within few seconds as a contact time in the nanoflow microreactor to give the lactone products with high regioselectivity without hydrolysis.     

Influence of hydroperoxides on the enantioselectivity of metal-catalyzed asymmetric Baeyer–Villiger oxidation and epoxidation with chiral ligands

Chiral hydroperoxides have a significant influence on the enantioselectivity of the metal-catalyzed asymmetric Baeyer–Villiger oxidation of cyclic ketones and the epoxidation of allylic alcohols, when chiral ligands are employed. If both the ligand and the hydroperoxide are enantiopure, the ligand determines the formation of the preferred product enantiomer in both reactions.     

Baeyer-Villiger反应中的氧化剂

对Baeyer-Villiger反应所用的氧化剂进行了总结,展示了其发展历史和反应特点以及在有机合成中的运用;分析了这一反应的不足之处并展望其未来的发展趋势。参考文献19篇。     

Oxidations catalyzed by phenylacetone monooxygenase from Thermobifida fusca

Several organic sulfides, ketones and other organic systems have been tested as substrates in oxidation reactions catalyzed by the recently discovered phenylacetone monooxygenase from Thermobifida fusca. The biocatalytic properties of this Baeyer–Villiger monooxygenase have been studied, revealing reactivity with a large range of sulfides and ketones. Oxidations of several sulfoxides, an amine and an organoboron compound were also observed. The enzyme is able to oxidize a number of sulfides with excellent enantioselectivity, demonstrating the catalytic potential of this novel biocatalyst.     

Silica/A153–SO3H: An efficient catalyst for the Baeyer–Villiger oxidation of cyclic ketones with hydrogen peroxide

Silica/A153–SO₃H was prepared and characterized by FT–IR, TG and SEM. It proved to be an efficient and recyclable heterogeneous catalyst in the Baeyer–Villiger (BV) oxidation of cyclic ketones with H₂O₂ as an oxidant. Catalysts with different silica particle sizes were also made comparisons in terms of catalytic effect.     

The kinetics,catalysis and inhibition of the Baeyer—Villiger reaction in the processes of liquid-phase oxidation of organic compounds

Literary data on kinetics, catalysis and inhibition of the oxidation reaction of carbonyl compounds with peroxy acids according to the Baeyer—Villiger reaction under aerobic liquidphase oxidation conditions have been considered and discussed. The main reaction channel involves a reversible formation of α-hydroxyperoxy ester and its rearrangement to an ester or a lactone. In the case of homolytic decomposition of α-hydroxyperoxy ester no esters are formed. At all steps the formation and transformation of α-hydroxyperoxy ester are catalyzed by carboxylic acids. The possibility of formation of the second intermediate, presumably dioxirane, is shown. Catalysts of the oxidation processes such as variable-valency metal salts influence the kinetics at all steps in the Baeyer—Villiger reaction. Inhibition of ester formation in the presence of cobalt and manganese salts is associated with catalysis of homolytic decomposition of peroxy acid and α-hydroxyperoxy ester.