- Nickel-catalyzed deallylation of aryl allyl ethers with hydrosilanes
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An efficient and mild catalytic deallylation method of aryl allyl ethers is developed, with commercially available Ni(COD)2 as catalyst precursor, simple substituted bipyridine as ligand and air-stable hydrosilanes. The process is compatible with a variety of functional groups and the desired phenol products can be obtained with excellent yields and selectivity. Besides, by detection or isolation of key intermediates, mechanism studies confirm that the deallylation undergoes η3-allylnickel intermediate pathway.
- Ding, Guangni,Fan, Sijie,Wang, Jingyang,Wang, Yu,Wu, Xiaoyu,Xie, Xiaomin,Yang, Liqun,Zhang, Zhaoguo
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supporting information
(2021/09/28)
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- Chemoselective Epoxidation of Allyloxybenzene by Hydrogen Peroxide Over MFI-Type Titanosilicate
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The chemoselective synthesis of 2-(phenoxymethyl)oxirane from allyloxybenzene is achieved with over 90 % yield in a sustainable reaction system using titanium-substituted silicalite-1 (TS-1) as a catalyst, hydrogen peroxide (H2O2) as an oxidant, and a mixture of MeOH/MeCN as a solvent at 40 °C. No acid-catalyzed side reactions prompted by the Lewis acidity of the Ti active site in TS-1 are observed. The TS-1 catalyst can also promote the formation of oxiranes from various p-substituted allyloxybenzenes in good yields. The reaction mechanism is investigated through the reaction with other allyloxy compounds. The results, which are supported by DFT calculations, indicate that an active species of Ti peroxides formed from the reaction of TS-1 with H2O2 selectively oxidizes the allyloxybenzene to 2-(phenoxymethyl)oxirane.
- Fujitani, Tadahiro,Hong, Dachao,Ito, Satoru,Ji, Xinyi,Kon, Yoshihiro,Nakashima, Takuya,Osuga, Ryota,Sato, Kazuhiko,Yokoi, Toshiyuki
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supporting information
(2020/04/15)
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- Structure-guided design, synthesis and evaluation of oxazolidinone-based inhibitors of norovirus 3CL protease
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Acute nonbacterial gastroenteritis caused by noroviruses constitutes a global public health concern and a significant economic burden. There are currently no small molecule therapeutics or vaccines for the treatment of norovirus infections. A structure-gu
- Damalanka, Vishnu C.,Kim, Yunjeong,Galasiti Kankanamalage, Anushka C.,Rathnayake, Athri D.,Mehzabeen, Nurjahan,Battaile, Kevin P.,Lovell, Scott,Nguyen, Harry Nhat,Lushington, Gerald H.,Chang, Kyeong-Ok,Groutas, William C.
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p. 881 - 890
(2017/12/26)
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- Regioselective Alkoxycarbonylation of Allyl Phenyl Ethers Catalyzed by Pd/dppb under Syngas Conditions
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A simple and regioselective synthesis of phenoxy esters and phenylthio esters is reported. The products are obtained by selective alkoxycarbonylation catalyzed by Pd2(dba)3, 1,4-bis(diphenylphisphino)butane (dppb), and syngas (CO/H2) in chloroform/alcohol. This methodology affords bifunctional products in good yield with excellent n-selectivity and without the need to use additives.
- Amézquita-Valencia, Manuel,Alper, Howard
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p. 3860 - 3867
(2016/05/24)
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- INHIBITORS OF FATTY ACID BINDING PROTEIN (FABP)
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The present invention relates to novel heterocyclic compounds as Fatty Acid Binding Protein ("FABP") inhibitors, pharmaceutical compositions comprising the heterocyclic compounds and the use of the compounds for treating or preventing a cardiovascular disease, a metabolic disorder, obesity or an obesity-related disorder, diabetes, dyslipidemia, a diabetic complication, impaired glucose tolerance or impaired fasting glucose. An illustrative compound of the present invention is shown below: (I)
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Page/Page column 143
(2010/06/15)
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- Microwave-accelerated Claisen rearrangement in bicyclic imidazolium [b-3C-im][NTf2] ionic liquid
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With microwaves, a chemically stable ionic liquid [b-3C-im][NTf2] recently developed in our laboratory was used as solvent and successfully applied to accelerate Claisen rearrangement reactions at high temperatures. In the presence of Lewis acid MgCl2, these thermal rearrangements could be achieved in similar reaction times but at lower temperature. For the microwaved reactions studied in this work, without scarifying isolated yields, the reaction times were significantly reduced from hours (by conventional heating) to ≤3 min. Our result also demonstrated that [b-3C-im][NTf2] ionic liquid was a useful solvent substitute and could be recycled multiple times for the studied rearrangement reaction at elevated temperatures.
- Lin, Yung-Lun,Cheng, Jen-Yen,Chu, Yen-Ho
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p. 10949 - 10957
(2008/02/13)
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- Preparation of aryl allyl ether in the recyclable ionic liquid [bmim]PF6
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The recyclable room temperature ionic liquid [bmim]PF6, namely 1-butyl-3-methyl-imidazolium hexafluorophosphate, is used as an alternative solvent to dipolar aprotic solvents for the synthesis of aryl allyl ether by the Williamson method.
- Zhou, Mei-Yun,Li, Yi-Qun
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p. 328 - 328
(2007/10/03)
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- Thermodynamic, spectroscopic, and density functional theory studies of allyl aryl and prop-1-enyl aryl ethers. Part 1. Thermodynamic data of isomerization
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A chemical equilibration study of the relative thermodynamic stabilities of seventy isomeric allyl aryl ethers (a) and (Z)-prop-1-enyl aryl ethers (b) in DMSO solution has been carried out. From the variation of the equilibrium constant with temperature the Gibbs energies, enthalpies, and entropies of isomerization at 298.15 K have been evaluated. Because of their low enthalpies, the (Z)-prop-1-enyl aryl ethers are strongly favored at equilibrium, the Gibbs energies of the a→b isomerization ranging from -12 to -23 kJ mol-1. The entropy contribution is negligible in most reactions, but occasionally small positive values less than +10 J K-1 mol-1 of the entropy of isomerization are found. The equilibration studies were also extended to involve two pairs of related isomeric ethers with a Me substituent on C(2) of the olefinic bond. The Me substituent was found to increase the relative thermodynamic stability of the allylic ethers by ca. 3.4 kJ mol-1.
- Taskinen, Esko
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p. 1824 - 1834
(2007/10/03)
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- The thermal [3, 3] claisen rearrangement of the 3-substituted phenyl allyl and propargyl ethers. The synthesis of 4-halobenzo[b]furans
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The thermal [3, 3] Claisen rearrangement of the 3-substituted phenyl allyl and propargyl ethers is regioselective. The major product of the reaction incorporates a 1, 2, 3-trisubstituted benzene ring. The 2-allenylphenol intermediates can be manipulated i
- Box, Vernon G. S.,Meleties, Panayiotis C.
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p. 2173 - 2183
(2007/10/03)
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- Convenient criterion for the distinction between electrophilic and electron transfer reactions of electron-rich alkenes
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Both experimental and theoretical studies confirm that the formation of aryl vinyl ether and aryl vinyl sulfide cation radicals from the corresponding neutral substrates correlates with the Brown σ+ parameters as opposed to Hammett σ values. Peak oxidation potentials for both classes of substrates correlate preferentially with σ+, as do gas-phase ionization energies calculated by both semi-empirical and ab initio methods. In contrast, the protonation energies of the same substrates, which relate to carbocation formation, correlate preferentially with σ values, as do rates of protonation and other electrophilic additions. These observations permit a sharp distinction between electrophilic and electron transfer reactions of these two common classes of electron-rich substrates. Using this criterion, the cycloadditions of tetracyanoethylene to these substrates are found to proceed via an electrophilic mechanism, rather than by a previously proposed electron transfer mechanism.
- Bauld, Nathan L.,Aplin, J. Todd,Yueh, Wang,Endo, Stephanie,Loving, Angie
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- A new and facile synthesis of chroman-3-ols, 3,4-dihydro-2H-[1]-benzopyran-3-ols
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o-Allyl phenols react with m-chloroperoxybenzoic acid (m-CPBA) in dry chloroform to give chroman-3-ols in a single step in good yields (93-96%).
- Satyanarayana,Prasad Rao Ch.,Krupadanam,Srimannarayana
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p. 1455 - 1464
(2007/10/02)
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- REACTIONS OF THIIRANES. X. REGIOSELECTIVITY OF RING-OPENING IN METHYL- AND VINYLTHIIRANES BY PHENOLS
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The effects of substituents in the phenol on the regioselectivity of the ring opening of methyl- and vinylthiiranes with phenols in the presence of 3-chloro-1-propene have been studied.Increasing the electron-donating properties of the substituent in the phenol increases the amount of the isomer corresponding to cleavage of the ring in accordance with Krasurskii's rule.The reaction rate was increased considerably when carried out in highly polar aprotic solvents.
- Tverdokhlebov, V. P.,Polyakova, N. Yu.,Tselinskii, I. V.
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p. 1258 - 1261
(2007/10/02)
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- REACTIONS OF THIIRANES. VII. MECHANISM OF THE OPENING OF THE THIIRANE RING BY R-PHENOLS IN THE PRESENCE OF 3-CHLORO-1-PROPENE WITH BASE CATALYSIS
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The kinetics of the opening of the thiirane ring by R-phenols in the presence of 3-chloro-1-propene under the conditions of base catalysis were studied.The effect of substituents in the aromatic ring on the rate constant for the formation of 4-thia-6-(R-phenoxy)-1-hexenes is described by a log k vs. ?- correlation.An isokinetic relationships is fulfilled in the investigated reaction series, and its features are discussed on the basis of the proposed reaction mechanism.
- Vergizova, T. V.,V'yunov, K. A.,Rodin, A. A.,Ginak, A. I.
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p. 2120 - 2125
(2007/10/02)
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