The first reductive cyclization by lithium aluminum hydride: stereospecific reductive cyclization of 1-(methoxycarbonylmethyl)imidazolidin-4-ones

The first LiAlH₄-driven reductive cyclization of the bifunctional 1-(methoxycarbonylmethyl)imidazolidin-4-ones, (−)-1a-c or(+)-1a-c, stereospecifically generated the corresponding 1,6-diaza-4-oxa-bicyclo[3.2.1]octanes, (−)-3a-c or(+)-3a-c, with a novel bicyclic system.     

Chiral Aluminum Complex Controls Enantioselective Nickel‐Catalyzed Synthesis of Indenes: C−CN Bond Activation

A chiral aluminum complex controlled, enantioselective nickel‐catalyzed domino reaction of aryl nitriles and alkynes proceeding by C?CN bond activation was developed. The reaction provides various indenes, bearing chiral all‐carbon quaternary centers, under mild reaction conditions in yields of 32 to 91 % and ee values within the 73–98 % range. The reaction mechanism and aspects of stereocontrol were investigated by DFT calculations.     

肉桂酸苄酯的合成

以肉桂酸为原料,经两步反应合成肉桂酸苄酯。第一步将肉桂酸制成肉桂酰氯,第二步将肉桂酰氯与苄醇反应制得肉桂酸苄酯。结构经IR,^1H NMR和MS确证。制备肉桂酰氯的最佳反应条件为：肉桂酸240mmol,n(肉桂酸)：n(亚硫酰氯)=1．00：1．08,反应温度60℃,反应时间30min。制备肉桂酸苄酯的最佳反应条件为：肉桂酰氯230mmol,n(肉桂酰氯)：n(苄醇)=1．0：1．2,反应温度15℃～20℃,反应时间1．5h,产率在91％以上。     

Acylzirconocene chloride: Formation of carbocycles by palladium-catalyzed cascade reaction

Acylzirconocene chloride complex as an acyl group donor reacts with ω-carbonyl α,β-enones or with bis-enones to give carbocyclic compounds under 10 mol% Pd(OAc)₂-catalyzed conditions, and each reaction was accelerated by the addition of a stoichiometric amount of Me₂Zn. The formation of the carbocycles from ω-carbonyl α,β-enones was considered to be a result of a series of reactions; (i) the formation of Pd(II)-intermediate by an electron transfer from the Pd(0)-catalyst to an α,β-enone function in an initial step, (ii) an acyl group transfer from the acylzirconocene complex to the Pd(II)-intermediate (transmetalation), (iii) the reductive elimination of Pd(0)-metal, and (iv) an intramolecular addition of metal enolate to ω-carbonyl group. On the other hand, the reaction of bis-enones with acylzirconocene chloride under the identical condition afforded reductive cyclization product, bicyclo[3.3.0] octane derivatives, in which acyl group from acylzirconocene complex was not incorporated.     

Aluminium(III) trifluoromethanesulfonate as an efficient catalyst for the intramolecular hydroalkoxylation of unactivated olefins: experimental and theoretical approaches

The Al(OTf)(3)-catalyzed cycloisomerization of unactivated unsaturated alcohols was studied from experimental and theoretical points of view. A series of cyclic ethers was obtained in excellent yields and regioselectivities. This catalyst system provides one of the most straightforward routes to cyclic ethers with Markovnikov-type regioselectivity under mild conditions. Theoretical and NMR studies were carried out in order to better determine the mechanism of this reaction. The NMR studies were in agreement with preferential complexation of Al(OTf)(3) to the oxygen atom of the unsaturated alcohol, but did not exclude complexation to the double bond of the alcohol. Theoretical calculations indicated strong acidification of the hydroxyl proton when Al(OTf)(3) was complexed to the alcohol oxygen atom. A plausible catalytic cycle for the Al(OTf)(3)-catalyzed intramolecular hydroalkoxylation of unactivated olefins is proposed.     

One-pot synthesis of iodine-substituted 1,4-oxazepines

A facile one-pot method for the synthesis of iodine-substituted 1,4-oxazepines is reported. When reacted with ZnCl₂ and I₂ in DCM at 40?°C, N-propargylic β-enaminones, prepared by the conjugate addition of propargylamine to α,β-alkynic ketones, underwent 7-exo-dig cyclization by zinc chloride and concomitant reaction with molecular iodine to afford 2-(iodomethylene)-2,3-dihydro-1,4-oxazepines in good to high yields. This cyclization was found to occur with broad scope of substrates and high tolerance of functional groups. The resulting iodine-containing 1,4-oxazepines can be further elaborated to more complex structures by subsequent cross-coupling reactions, which may provide a platform for biological studies.     

聚氯乙烯三氯化铁树脂催化合成肉桂酸甲酯

在聚氯乙烯三氯化铁催化下由肉桂酸和甲醇发生酯化合成了肉桂酸甲脂,当０．０２ｍｏｌ．肉桂酸,０．１０ｍｏｌ甲醇和１．５ｇ催化剂一起回流加热７．０ｈ时,产品收率达８４．４％。     

苯酞类化合物重排反应的研究——————3－位烷基取代苯 酞的重排反应

发现了3-正丁基苯酞在三氯化铝作用下进行重排反应生成1-甲基-5-羧基四氢萘,并提出了氢迁移的重排反应机制。研究了3-位不同烷基取代的苯酞类化合物在三氯化铝作用下的重排反应。在重排过程中,既有氢迁移,也会有烷基迁移,这取决于形成的碳正离子的稳定性。     

Concise Synthesis of Photocleavable Molecular Tag for Laser Desorption Ionization Mass Spectrometry via Fries Reaction

Abstract

A new synthetic route for the photocleavable molecular tag for laser desorption ionization mass spectrometry (LDI-MS) was achieved using the Fries reaction of 2,6-dimethylphenyl ester as its key reaction. Zirconium chloride was used as uniquely efficient adjuvant to promote the reaction. The molecular tag was obtained in five steps without chromatographic purification.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

Facile Synthesis of 3,3‐Dialkyl‐6‐phenyl‐imidazopyridinones

A series of novel 3,3‐dialkylated imidazopyridinones bearing 6‐aryl groups were designed as mimetics of active progesterone antagonists, 3,3‐disubstituted‐5‐arylindoles. The four‐step synthetic route is described. The key steps are base‐catalyzed cyclization, base‐catalyzed alkylation, and Suzuki coupling reaction.