- Influence of phase transfer catalyst structure on selectivity
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A concise review is given of systematic studies concerned with the tuning of regio-, "frequentio-", chemo-, and diastereoselectivity by the structure or type of phase transfer catalyst. - Keywords: phase transfer catalysis; regioselectivity; selectivity control; stereoselectivity; C/O-alkylation; C/N-alkylation.
- Dehmlow, E. V.
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- Ionic liquids as solvents for the regioselective O-alkylation of C/O ambident nucleophiles
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The reaction of sodium β-naphthoxide with benzyl halides in molten tetraalkylammonium or phosphonium halides (at 110°C or below) leads to a highly regioselective O-alkylation. These new solvents, which can be quantitatively recovered at the end of the reaction, mimic the behaviour of dipolar aprotic solvents.
- Badri, Meryam
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- HIGHLY SELECTIVE BENZILATIONS OF β-NAPHTHOXIDE ANION IN HETEROGENEOUS MEDIA
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Each of the four products resulting from the benzylation of the ambident β-naphthoxide anion can be efficiently and selectively obtained in mild an economical conditions by a judicious choice of the solid base: LiOH, LiOtBu or KOH-Aliquat.
- Bram, G.,Loupy, A.,Sansoulet, J.,Vaziri-Zand, F
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- THE ROLE HYDROGEN BONDING IN THE AUTOOXIDATION AND ALKYLATION OF 2-NAPHTHOLS
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The powerful hydrogen bond electron donor fluoride ion assists the O-alkylation of 2-naphthols but inhibits the autooxidation of 1-alkyl-2-naphthols.These observations may be explained in terms of the nature of the OHF- hydrogen bond.
- Jazzaa, Abdulaziz Al,Clark, James H.,Miller, Jack M.
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- Mechanism of Reactions Promoted by Polymer-Supported Phase-Transfer Catalysts
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Kinetic measurements indicate that the ratio of C- vs.O-alkylation of β-naphthoxide is not a reliable polarity test for polymer-supported phase-transfer catalysis because of the competitive noncatalyzed reactions.A reliable test is the C/O-alkylation of phenoxide.Reactions carried out in toluene-water in the presence of stoichiometric amounts of polystyrene-supported quaternary phosphonium salts 2 and 3 afford only O-alkylation products.Stoichiometric reactions give significant amounts of C-alkylation with 2 or 3 in aqueous ethanol or with immobilized polar catalysts 4 and 5 in toluene-water.Hydration measurements agree with the essentially hydrophobic character of polystyrene-supported phosphonium catalysts 2 and 3.These results confirm our previous conclusion that phase-transfer catalysis follows identical mechanisms both in the presence of soluble and polymer-supported catalysts.In the latter case the reaction should occur within an organic solvation shell firmly surrounding the catalytic site, rather than in an aqueous solvation sphere or at the interface.
- Montanari, Fernando,Quici, Silvio,Tundo, Pietro
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- Catalytic Tandem and One-Pot Dehydrogenation-Alkylation and -Insertion Reactions of Saturated Hydrocarbons with Alcohols and Alkenes
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The ruthenium-hydride catalyst has been successfully used for the tandem sp3 C-H dehydrogenation-alkylation reaction of saturated hydrocarbon substrates with alcohols to form the alkyl-substituted alkene and arene products. The analogous one-pot dehydrogenation-insertion of saturated ketones with alkenes and dienes directly yielded synthetically useful 2-alkylphenol and benzopyran products in a highly regio- and stereoselective manner without forming any wasteful byproducts. (Chemical Equation Presented).
- Kim, Junghwa,Pannilawithana, Nuwan,Yi, Chae S.
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p. 8395 - 8398
(2016/12/16)
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- 6-HYDROXY-2-NAPHTHALENYL FLUORENE DERIVATIVES AND LENS AND CAMERA MODULE USING THE SAME
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Disclosed herein are 6-hydroxy-2-naphthalenyl fluorene derivatives and a lens and a camera module using the same.
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- Microwave-Assisted solid-liquid phase alkylation of naphthols
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The microwave promoted alkylation of 1- and 2-naphthols with benzyl, butyl, ethyl and isopropyl halides in the presence of an alkali carbonate may result in O- and C-Alkylated products. The alkylations were O-selective in the presence of K2CO3 in acetonitrile as the solvent and in the absence of phase transfer catalyst. The alkylations utilizing butyl and ethyl halides were also O-selective in solventless accomplishment and in the presence of triethylbenzylammonium chloride.
- Balint, Erika,Kovacs, Orsolya,Drahos, Laszlo,Keglevich, Gyoergy
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p. 330 - 336
(2013/07/26)
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- An efficient method for the preparation of versatile building blocks: 1-substituted 2,2-dimethoxyethylamine hydrochlorides1
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A novel method for the preparation of 1-substituted 2,2-dimethoxyethylamine hydrochlorides was developed. The method includes three highly efficient steps: (1) direct use of aqueous (MeO)2CHCHO for the preparation of N,O-acetal by condensation with Betti
- Liu, Bo,Su, Deyong,Cheng, Guolin,Liu, Hui,Wang, Xinyan,Hu, Yuefei
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scheme or table
p. 3227 - 3232
(2010/02/27)
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- Convenient synthesis of 1-arylmethyl-2-naphthols
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A new environmentally benign, two-step procedure for the synthesis of 1-arylmethyl-2-naphthols in good to excellent yield is reported. It involves microwave-assisted facile formation of Mannich bases of 2-naphthol under solvent-free conditions and subsequ
- Paul, Nawal K.,Dietrich, Lindsay,Jha, Amitabh
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p. 877 - 888
(2007/10/03)
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- Applications of surfactant-modified clays to synthetic organic chemistry
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Two triphase catalysts (SLL) have been developed for organic phase-aqueous phase reactions catalyzed by suitable modified clay (solid phase). These triphase catalysts have been applied to nucleophilic displacement on activated (benzylic) as well as unactivated organic halides and provide a convenient and effective method of preparation of the corresponding products. Other useful transformations to, which these triphase catalysts have been successfully applied are the synthesis of 9,9-dichloro bicyclo[6.1.0]nonane, O-alkylation and C-alkylation of β-naphthol.
- Ghiaci,Sedaghat,Kalbasi,Abbaspur
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p. 5529 - 5534
(2007/10/03)
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- o-(α-Benzotriazolylalkyl)phenols: Versatile Intermediates for the Synthesis of Substituted Phenols
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Phenols and naphthols are benzotriazolylmethylated by 1-(hydroxymethyl)-1H-benzotriazole (13) (a formaldehyde derivative) in the o- or (if both o-positions are occupied) in the p-position.The reaction can be extended to other aldehydes in the case of the naphthols.The methylene group in the o-(benzotriazolylmethyl)phenols can be lithiated (but only after trimethylsilyl protection of the hydroxy group) and then substituted by various electrophiles.The benzotriazole residues in both the primary products and in their substituted derivatives can be displaced by the alkylanions of Grignard reagents or by hydride ions allowing the elaboration of many new types of substituted phenols. Key Words: Lithiation/ Mannich reaction/ Alkylation/ Grignard reaction/ Condensation
- Katritzky, Alan R.,Lan, Xiangfu,Lam, Jamshed N.
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p. 1809 - 1817
(2007/10/02)
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- Molecular Rearrangements: Part I - Pyrolysis of Dibenzyl Sulphide
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Thermal rearrangement of dibenzyl sulphide in the absence of promoters has been thoroughly investigated and found to involve cleavage of the C-S bonds followed by a series of hydrogen abstraction, coupling, dehydrogenation and cyclisation reactions.The products isolated include H2S, toluene, benzaldehyde, dibenzyl, stilbene and tetraphenylthiophene.Benzylation products are also isolated when thermolysis is carried out in aromatic solvents such as β-naphthol and isoquinoline.A suitable mechanism has been suggested to account for the obtained products.It is noteworthy that no isomer redistribution precedes the coupling reactions.
- Abdel-Wahab, Aboel-Magd A.,Abdel-Rahman, Abdu E.
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p. 636 - 639
(2007/10/02)
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- Regioselectivity of the Alkylation of Ambident Anionic Species on Alumina or in the Presence of 'Solid Hexamethylphosphoric Triamide'
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C-Alkylation of the acetoacetate anions and of sodium naphthoxide is highly favoured on alumina, while O-alkylation of the acetoacetate anion predominates in tetrahydrofuran in the presence of solid hexamethylphosphoric triamide.
- Bram, Georges,Geraghty, Niall,Nee, Gerard,Seyden-Penne, Jacqueline
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p. 325 - 326
(2007/10/02)
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- Synthetic Routes to Derivatives of Polycyclic Aromatic Hydrocarbons Using Isobenzofurans as Transient Reactive Intermediates
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The known equilibrium between the tautomers benzalphthalan (1) and 1-benzylisobenzofuran (2) has been exploited as a synthetic route to novel substituted polycyclic aromatic compounds.The isobenzofuran was captured in a series of Diels-Alder reactions to
- Smith, James G.,Welankiwar, Sudha S.,Shantz, Barry S.,Lai, Eric H.,Chu, Noreen G.
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p. 1817 - 1824
(2007/10/02)
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