- Polymer-anchored mononuclear and binuclear CuII Schiff-base complexes: Impact of heterogenization on liquid phase catalytic oxidation of a series of alkenes
-
Liquid phase catalytic oxidation of a number of alkenes, for example, cyclohexene, cis-cyclooctene, styrene, 1-methyl cyclohexene and 1-hexene, was performed using polymer-anchored copper (II) complexes PS-[Cu (sal-sch)Cl] (5), PS-[Cu (sal-tch)Cl] (6), PS-[CH2{Cu (sal-sch)Cl}2] (7) and PS-[CH2{Cu (sal-tch)Cl}2] (8). Neat complexes [Cu (sal-sch)Cl] (1), [Cu (sal-tch)Cl] (2), [CH2{Cu (sal-sch)Cl}2] (3) and [CH2{Cu (sal-tch)Cl}2] (4) were isolated by reacting CuCl2·2H2O with [Hsal-sch] (I), [Hsal-tch] (II), [H2bissal-sch] (III) and [H2bissal-tch] (IV), respectively, in refluxing methanol. Complexes 1–4 have been covalently anchored in Merrifield resin through the amine nitrogen of the semicarbazide or thiosemicarbazide moiety. A number of analytical, spectroscopic and thermal techniques, such as CHNS analysis, Fourier transform-infrared, UV–Vis, PMR, 13C-NMR, electron paramagnetic resonance, scanning electron microscopy, energy-dispersive X-ray analysis, thermogravimetric analysis, atomic force microscopy, atomic absorption spectroscopy, and electrospray ionization-mass spectrometry, were used to analyze and establish the molecular structure of the ligands (I)–(IV) and complexes (1)–(8) in solid state as well as in solution state. Grafted complexes 5–8 were employed as active catalysts for the oxidation of a series of alkenes in the presence of hydrogen peroxide. Copper hydroperoxo species ([CuIII (sal-sch)-O-O-H]), which is believed to be the active intermediate, generated during the catalytic oxidation of alkenes, are identified. It was found that supported catalysts are very economical, green and efficient in contrast to their neat complexes as well as most of the recently reported heterogeneous catalysts.
- Maurya, Abhishek,Kesharwani, Neha,Kachhap, Payal,Mishra, Vivek Kumar,Chaudhary, Nikita,Haldar, Chanchal
-
-
- A 2-heptanone synthetic method
-
The invention discloses a chemical synthetic method, specifically a method for synthesizing 2-heptanone by using acetone and butyraldehyde as raw materials. According to the invention, acetone and butyraldehyde which used as raw materials undergo a cross aldol condensation reaction under catalysis of solid base, and reaction products further undergo dehydration and catalytic hydrogenation so as to prepare 2-heptanone. The invention has advantages as follows: technological process is shortened by the technology; generation of an acid-containing waste liquid is avoided; generation of by-products is minimized; investment in equipment is reduced; and production costs of the product are decreased.
- -
-
Paragraph 0043
(2017/01/26)
-
- Activation of Chiral (Salen)AlCl Complex by Phosphorane for Highly Enantioselective Cyanosilylation of Ketones and Enones
-
Phosphoranes 2 are identified as a class of effective Lewis bases to activate chiral (salen)AlCl complex 1 to enhance its electrophilicity. Accordingly, a three-component catalyst system consisting of complex 1, phosphorane 2e, and Ph3PO is developed as a powerful tool for asymmetric ketone cyanosilylation. In particular, an unprecedented highly enantioselective cyanosilylation of linear aliphatic ketones is achieved. A tandem Wittig-cyanosilylation sequence starting from phosphorane 2a and enals 10 is further achieved, which internally utilizes the Ph3PO byproduct and remaining phosphorane 2a as cocatalysts for cyanosilylation of α,β,γ,δ-unsaturated enones, providing atom-efficient access to valuable chiral conjugated dienes and enynes. The high efficiency of the cyanosilylation originates from orthogonal activation of both (salen)AlCl complex 1 and cyanotrimethylsilane by the phosphorane and Ph3PO, respectively. This mechanistic insight is supported by NMR, MS, and ReactIR analyses and DFT calculations. Furthermore, the formation of charged complexes through the activation of chiral complex 1 by phosphorane 2a is confirmed by electrical conductivity experiments.
- Zeng, Xing-Ping,Cao, Zhong-Yan,Wang, Xin,Chen, Long,Zhou, Feng,Zhu, Feng,Wang, Cui-Hong,Zhou, Jian
-
supporting information
p. 416 - 425
(2016/01/25)
-
- Enantioselective [4 + 2] cycloaddition of cyclic N-sulfimines and acyclic enones or ynones: A concise route to sulfamidate-fused 2,6-disubstituted piperidin-4-ones
-
A concise route to valuable sulfamate-fused 2,6-disubstituted piperidin-4-ones or 2,3-dihydropyridin-4(1H)-ones in good yield with high diastereo- and enantioselectivity is presented. The combination of chiral primary amine and o-fluorobenzoic acid efficiently promoted an asymmetric [4 + 2] cycloaddition reaction of N-sulfonylimines and enones or ynones. The cycloaddition reaction between cyclic N-sulfonylimines and ynones is first reported.
- Liu, Yong,Kang, Tai-Ran,Liu, Quan-Zhong,Chen, Lian-Mei,Wang, Ya-Chuan,Liu, Jie,Xie, Yong-Mei,Yang, Jin-Liang,He, Long
-
p. 6090 - 6093
(2014/01/06)
-
- Processes for preparing beta-hydroxy-ketones and alpha,beta-unsaturated ketones
-
Processes for producing β-hydroxy-ketones and α,β-unsaturated ketones are disclosed which comprise the crossed condensation of an aldehyde with a ketone in the presence of a hydroxide or alkoxide of alkali metal or an alkaline earth metal as catalyst. The products of the process, β-hydroxy-ketones and α,β-unsaturated ketones, are useful for the preparation of many commercially important products in the chemical process industries including solvents, drug intermediates, flavors and fragrances, other specialty chemical intermediates.
- -
-
-
- PROCESSES FOR THE PREPARATION OF HIGHER MOLECULAR WEIGHT SATURATED KETONES
-
Continuous single-step processes for producing higher molecular weight ketones are disclosed that involve a liquid-phase crossed condensation of an aldehyde with a ketone in the presence of a hydrogenation catalyst and a small amount of a catalyst comprising a concentrated hydroxide or alkoxide of an alkali-metal (from Group 1 or Group IA of the Periodic Table of the Elements) or alkali-earth metal (from Group 2, or Group IIA of the Periodic Table of the Elements), wherein the amount of water provided to the reaction mixture, or reaction zone, is relatively low, with respect to the total initial weight of the reaction mixture. The reaction may be carried out in the absence of solubilizing agents or phase transfer agents. The product mixture is largely free of by-products resulting from further condensation reactions of the desired ketone product or intermediates, and free of the self-condensation products of the reactant aldehyde, that are afterward difficult to remove from the reaction mixture.
- -
-
Page/Page column 9-11
(2008/06/13)
-
- Processes for the preparation of higher molecular weight ketones
-
Processes for producing higher molecular weight ketones are disclosed that include the steps of feeding an aldol catalyst solution, a lower molecular weight aldehyde, and a lower molecular weight ketone, through a reactor provided with a solid hydrogenation catalyst and hydrogen gas; recovering a liquid reactor effluent containing the higher molecular weight ketone as a reaction product; and recycling a portion of the recovered liquid reactor effluent back through the reactor.
- -
-
-
- Direct asymmetric aldol reactions of acetone using bimetallic zinc catalysts
-
(Equation presented) The enantioselective aldol reaction using a novel binuclear zinc catalyst of acetone with several aldehydes gave products in good yields (62-89%) with a high level of enantioselectivity (ee = 76-92%).
- Trost, Barry M.,Silcoff, Elliad R.,Ito, Hisanaka
-
p. 2497 - 2500
(2007/10/03)
-
- Dynamic kinetic resolution of allylic alcohols mediated by ruthenium- and lipase-based catalysts.
-
An enzyme-metal combo reaction has been developed for the dynamic kinetic resolution of allylic alcohols in which racemic substrates are transformed by a lipase and a ruthenium complex in the presence of an acyl donor to allylic acetates of high optical purity in over 80% yield.
- Lee,Huh,Kim,Jung,Koh,Park
-
p. 2377 - 2379
(2007/10/03)
-
- Synthesis of α,β-unsaturated ketone from α-iodo ketone using photoirradiation
-
Irradiation of α-iodo ketone in hexane under a nitrogen atmosphere with a high-pressure mercury lamp (λ>300nm) at room temperature afforded the corresponding α,β-unsaturated ketones in good yield. This reaction affords a new, clean and convenient synthetic method for the α,β-unsaturated ketone.
- Ji, Shun-Jun,Takahashi, Eiji,Takahashi, T. Tomoyoshi,Horiuchi, C. Akira
-
p. 9263 - 9266
(2007/10/03)
-
- REACTION OF HOMOALLYLIC COMPOUNDS OF TIN WITH ACYLATING AGENTS
-
In the reaction of homoallylic organotin compounds with carboxylic acid anhydrides and chlorides in the presence of Lewis acids cyclopropyl methyl ketones are formed with α,β-unsaturated ketones and β-chloro ketones as impurities.The ratio of the reaction products depends on the temperature, the structure of the reagents, and the type of catalyst.
- Ivashchenko, N. B.,Polunin, E. V.,Kashin, A. N.
-
p. 546 - 550
(2007/10/02)
-
- COMPOUNDS WITH A HERBAL ODOR III. CIS-ALKENES WITH AN OXYGEN FUNCTION AT THE β POSITION AND THEIR SYNTHESIS BY HYDROGENATION OF DIENE PRECURSORS AT CHROMIUM HEXACARBONYL
-
During the hydrogenation of dienes with oxygen functions at the α position in the presence of chromium hexacarbonyl 1,4-addition of hydrogen to the diene system occurs, and this leads to the corresponding cis-monoene derivatives.In the case of dienes with hydroxyl, alkoxyl, acetal, and ester groups the product yield approaches quantitative; the hydrogenation of similar oxo and acyloxy derivatives is less satisfactory.Many representatives of the synthesized compounds, in which the cis-disubstituted double bond is separated from the oxygen-containing functional group by two carbon atoms, have a herbal odor.
- Vasil'ev, A. A.,Cherkaev, G. V.
-
p. 834 - 840
(2007/10/02)
-