低价钛诱导的芳香邻二酮及α-羟基酮的还原偶联反应

Treatment of aromatic 1 , 2-diketones or aromatic a-hydroxy ketones with an activated low-valent titanium reagent, prepared by reduction of TiCl3·1/3AlCl3 with a Zn-Cu reagent, gave an intermolecular coupling reaction leading to the (Z)-1, 2.3.4-tetraaryl-2-butenes. Apossible coupling reaction process was proposed for the aromatic a-hydroxy ketones.     

Selective Hydrogenation and Hydrodeoxygenation of Aromatic Ketones to Cyclohexane Derivatives Using a Rh@SILP Catalyst

Rhodium nanoparticles immobilized on an acid‐free triphenylphosphonium‐based supported ionic liquid phase (Rh@SILP(Ph₃‐P‐NTf₂)) enabled the selective hydrogenation and hydrodeoxygenation of aromatic ketones. The flexible molecular approach used to assemble the individual catalyst components (SiO₂, ionic liquid, nanoparticles) led to outstanding catalytic properties. In particular, intimate contact between the nanoparticles and the phosphonium ionic liquid is required for the deoxygenation reactivity. The Rh@SILP(Ph₃‐P‐NTf₂) catalyst was active for the hydrodeoxygenation of benzylic ketones under mild conditions, and the product distribution for non‐benzylic ketones was controlled with high selectivity between the hydrogenated (alcohol) and hydrodeoxygenated (alkane) products by adjusting the reaction temperature. The versatile Rh@SILP(Ph₃‐P‐NTf₂) catalyst opens the way to the production of a wide range of high‐value cyclohexane derivatives by the hydrogenation and/or hydrodeoxygenation of Friedel–Crafts acylation products and lignin‐derived aromatic ketones.     

低价钛诱导的芳香邻二酮及α－羟基酮的还原偶联反应

低价钛诱导的芳香邻二酮及α－羟基酮的还原偶联反应侯自杰，刘利军，张建华，李裕林（兰州大学有机化学研究所，兰州，７３００００）关键词低价钛，芳香邻二酮，芳香α－羟基酮，偶联羰基化合物在低价钛诱导下的还原偶联反应已有深入研究并在有机合成中得到广泛应用［１...     

Synthesis and Properties of Benzylidene Derivatives of Terpenoid Ketones

Optically active benzylidene derivatives of camphor and menthone were obtained in preparative yields by condensation of the ketones with aromatic aldehydes in DMSO in the presence of t-BuOLi. The synthesized ,-unsaturated ketones show high specific rotation and thus are suitable to be applied as doping component to liquid-crystalline compositions.     

One-Pot Synthesis of 2-Alkylsulfanyldihydrofuran Derivatives from Tetracyanocyclopropyl Ketones

Russian Journal of Organic Chemistry - Successive treatment of 3-acylcyclopropane-1,1,2,2-tetracarbonitriles with sodium hydrogen carbonate and alkylmercaptan in water environment results in the...     

Synthesis of Aromatic Ketones from Aromatic Compounds Using Vanadium‐Containing Mesoporous Silicates

Aromatic ketones were synthesized from aromatic compounds via liquid‐phase oxidation at 60 °C and 1 atm over vanadium‐containing MCM‐41 catalysts using a batch reactor. The catalysts were prepared by direct hydrothermal (4V‐MCM‐41) and wet impregnation (9V/MCM‐41) methods. Their physico‐chemical properties were determined with various characterization techniques. For the oxidations of all substrates in this work, 4 V‐MCM‐41 exhibits superior catalytic performance than 9 V/MCM‐41 due to its larger values of unit cell parameter, BET surface area, and vanadium dispersion as well as stronger oxidation ability of vanadium‐oxygen species. Apparently, the single site, isolated vanadium centers in 4V‐MCM‐41 possess much higher activity (based on the turnover number) than those containing more vanadium atoms in 9V/MCM‐41. In addition, the substrate activities decrease in the order of diphenylmethane > fluorene > 9,10‐dihydroanthracene > ethylbenzene ≥ 4‐nitroethylbenzene, which are attributed to their distinct molecular structures.     

几种芳香型三环二萜化合物的半合成

芳香型三环二萜;半合成;(±)-甲氧基罗汉松烷三烯     

多酯基取代的叶绿素类二氢卟吩衍生物的合成

以脱镁叶绿酸-a甲酯为起始原料,通过碱性条件下的水解开环、空气氧化和重排反应,分别合成了红紫素-7三甲酯和二氢卟吩-p6三甲酯.然后对其C(3)-乙烯基、20-meso-位、12-位甲基以及尾端酯基进行化学修饰,通过亲电加成、亲电取代、1,3-偶极环加成和氧化重排等反应,完成10种具未见报道的的叶绿素类二氢卟吩衍生物,其化学结构均经UV,IR,1H NMR光谱及元素分析予以表征.     

芳香酮的不对称还原*

本文从化学方法和生物方法两个角度,化学催化法、手性试剂法和酶催化法三个方面综述了近年来芳香酮的不对称还原进展。文章概述了芳香酮取代基的电子效应与空间效应、手性催化剂和手性试剂的结构、反应体系等对产物光学活性的影响,以及全细胞酶、分离酶等不同生物催化体系中芳香酮结构对产物光学活性的影响,并展望了不对称还原的研究及应用前景。     

新型芳香吲唑酮类化合物的合成与表征

以p-取代苯胺为原料,经重氮化反应后再与2-氯乙酰乙酸乙酯反应制得(Z)-4-[2-(1-氯-2-乙氧基-2-羰亚甲基)肼基]-取代苯(2a～2i);在无水乙醇中,2a～2i分别与5,5-二甲基-1,3-环己二酮发生环化反应合成了9个新型的芳香吲唑类化合物(3a～3i),其结构经1H NMR和MS表征.     

A Reductive 1,2 Transposition of Acyclic Ketones

Earlier we noted that the hydroboration of the trimethylsilyl enol ether of an acyclic ketone results in an elimination of a trimethylsiloxyborane moiety with the subsequent formation of an olefin.^1,2 The olefin formed then undergoes hydroboration giving a monoalcohol upon oxidation. (eq 1) We wish to report here on the utility of this sequence, illustrated in eq 1, in the reductive 1,2 transposition of acyclic ketones.³     

Efficient Synthesis of Aromatic Carboxylic Acids from Aryl Ketones in Ionic Liquid

Conversion of aryl ketones to the corresponding aromatic carboxylic acids has been achieved using sequential treatment of HDNIB and urea–hydrogen peroxide in [bmim]BF₄ ionic liquid.     

General Synthesis of Secondary Alkylamines by Reductive Alkylation of Nitriles by Aldehydes and Ketones

The development of C−N bond formation reactions is highly desirable due to their importance in biology and chemistry. Recent progress in 3d metal catalysis is indicative of unique selectivity patterns that may permit solving challenges of chemical synthesis. We report here on a catalytic C−N bond formation reaction—the reductive alkylation of nitriles. Aldehydes or ketones and nitriles, all abundantly available and low-cost starting materials, undergo a reductive coupling to form secondary alkylamines and inexpensive hydrogen is used as the reducing agent. The reaction has a very broad scope and many functional groups, including hydrogenation-sensitive examples, are tolerated. We developed a novel cobalt catalyst, which is nanostructured, reusable, and easy to handle. The key seems the earth-abundant metal in combination with a porous support material, N-doped SiC, synthesized from acrylonitrile and a commercially available polycarbosilane.     

Carbene-Catalyzed Enantioselective Aromatic N-Nucleophilic Addition of Heteroarenes to Ketones

The aromatic nitrogen atoms of heteroarylaldehydes are activated by carbene catalysts to react with ketone electrophiles. Multi-functionalized cyclic N,O-acetal products are afforded in good to excellent yields and optical purities. Our reaction involves the formation of an unprecedented aza-fulvene-type acylazolium intermediate. A broad range of N-heteroaromatic aldehydes and electron-deficient ketone substrates works effectively in this transformation. Several of the chiral N,O-acetal products afforded through this protocol exhibit excellent antibacterial activities against Ralstonia solanacearum (Rs) and are valuable in the development of novel agrichemicals for plant protection.     

羟基查尔酮类衍生物的合成

4-羟基苯乙酮或2,4-二羟基苯乙酮与取代苯甲醛在乙二醇溶液中,以硼酸为催化剂,于110～120℃反应6 h,再经柱分离精制得羟基查尔酮衍生物.产物经红外光谱、核磁共振谱、质谱确认结构.此法合成虽然收率不太高,但利用此法可更简便地一步合成出羟基查尔酮类衍生物.