- Diol-Ritter Reaction: Regio- And Stereoselective Synthesis of Protected Vicinal Aminoalcohols and Mechanistic Aspects of Diol Monoester Disproportionation
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The well-known epoxide-Ritter reaction generally affords oxazolines with poor to average regioselectivity. Herein, a mechanism-based study of the less known diol-Ritter reaction has provided a highly regioselective procedure for the synthesis of 1-vic-amido-2-esters from either terminal epoxides or 1,2-diols via Lewis acid-catalyzed monoesterification. When treated with a stoichiometric Lewis acid catalyst (BF3), these diol monoesters form dioxonium cation intermediates that are ring-opened with nitrile nucleophiles to form nitrilium intermediates, which undergo rapid and irreversible hydration to give the desired amidoesters. Diester byproduct formation is irreversible and appears to occur through disproportionation of diol monoester. With chiral epoxide starting materials, the formation of amidoester occurs with retention of configuration and no apparent erosion of optical purity as determined by single-crystal X-ray analyses and chiral chromatography, respectively. The direct access to chiral vic-amidoesters is especially practical with regard to the synthesis of antibacterial oxazolidinone analogues of the Zyvox antimicrobial family.
- Ondari, Mark E.,Klosin, Jerzy,Kruper, William R.,Lysenko, Ivan,Thomas, Pulikkottil J.,Cheng, Kevin,Abboud, Khalil A.,Kruper, William J.
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p. 2063 - 2074
(2021/10/20)
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- A highly efficient protocol for regioselective ring-opening of epoxides with alcohols, water, acetic acid, and acetic anhydride catalyzed by SbF3
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SbF3as an efficient catalyst has been used for regioselective alcoholysis, acetolysis and hydrolysis of epoxides to the corresponding β-alkoxy, β-acetoxy alcohols, and 1,2-diols in high to excellent yields. This study also represents a convenient synthesis of vic-diacetates from ring-opening of epoxides with acetic anhydride.
- Zeynizadeh, Behzad,Gilanizadeh, Masumeh,Aminzadeh, Farkhondeh Mohammad
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p. 1051 - 1056
(2016/07/06)
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- Heterogeneous acidic and eco-friendly reagents for mild and convenient conversion of epoxides to 1,2-diacetates
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A highly regioselective ring-opening of epoxides with acetic anhydride in the presence of hydrated disodium hydrogen phosphate and sodium hydrogen sulfate as efficient and eco-friendly reagents is described. The reactions are clean and lead to 1,2-diacetates in high to excellent yields.
- Gilanizadeh, Masumeh,Zeynizadeh, Behzad
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p. 296 - 298
(2016/07/06)
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- Solventless acetylation of alcohols and phenols catalyzed by supported iron oxide nanoparticles
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Supported iron oxide nanoparticles on silicate catalysts were found to be efficient and easily recoverable materials in the acetylation of alcohols and phenols to their corresponding acetyl compounds using acetic anhydride under mild and solvent-less conditions. The supported iron oxide nanoparticles could be easily recovered from the reaction mixture and reused ten times without any loss in activity.
- Rajabi, Fatemeh,Luque, Rafael
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p. 129 - 132
(2014/01/06)
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- One-pot catalytic conversion of epoxides to 1,2-diacetates with hydride transferring agents in acetic anhydride
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Direct transformation of structurally different epoxides to the corresponding 1,2-diacetates was studied with catalytic amounts of NaBH 4, LiAlH4, CaH2, and NaH. The reactions were carried out in refluxing acetic anhydride within 1.5-2.5h to give vic-diacetates in good to excellent yields. Conversion of R-(+)-styrene oxide to S-(+)-1,2-diacetoxy-1-phenylethane was carried out with good yield and stereospecificity with the NaBH4/Ac2O system at 0°C.
- Zeynizadeh, Behzad,Sadighnia, Leila
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experimental part
p. 637 - 644
(2011/03/21)
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- Mild organic ammonium tribromide-mediated regioselective ring opening of epoxides with alcohols, water, acetic anhydride, and amines under solvent-free reaction conditions
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Organic ammonium tribromide (OATB), N-methylpyrrolidine-2-one hydrotribromide (MPHT) was found to be an efficient catalyst for the regioselective ring opening of epoxides with various nucleophiles under solvent free conditions. This procedure occurs under neutral and mild reaction conditions with out adding any additive and afforded high yields of products.
- Singhal, Sweety,Jain, Suman L.,Sain, Bir
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experimental part
p. 1829 - 1837
(2011/06/19)
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- A green protocol for catalytic conversion of epoxides to 1,2-diacetoxy esters with phosphomolybdic acid alone or its supported on silica gel
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Catalytic conversion of structurally different epoxides to the corresponding 1,2-diacetoxy esters was carried out readily with phosphomolybdic acid alone or its supported on SiO2. The reactions were carried out under solvolytic or solvent free conditions within 5-15 min at room temperature. The product 1,2-diacetates were obtained in high to excellent yields. Supporting of phosphomolybdic acid on SiO2 showed the better catalytic activity than Al2O3. Conversion of optically pure R-(+)-styrene oxide to S-(+)-1,2-diacetoxy-1-phenylethane was carried with phosphomolybdic acid in high yield and stereospecificity.
- Zeynizadeh, Behzad,Sadighnia, Leila
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experimental part
p. 2644 - 2648
(2010/12/25)
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- A heterogeneous cobalt(II) Salen complex as an efficient and reusable catalyst for acetylation of alcohols and phenols
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Acetylation of various alcohols and phenols was performed successfully using an immobilized cobalt(II) catalyst in high yield. The catalyst shows high thermal stability and was also recovered and reused at least 10 times without any considerable loss of activity.
- Rajabi, Fatemeh
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scheme or table
p. 395 - 397
(2009/05/07)
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- Alumina-supported molybdenum (VI) oxide: An efficient and recyclable heterogeneous catalyst for regioselective ring opening of epoxides with thiols, acetic anhydride, and alcohols under solvent-free conditions
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An efficient and simple protocol for regioselective ring opening of epoxides with thiols, acetic anhydride, and alcohols using 16wt% MoO3 supported on alumina as a recyclable catalyst is described. Copyright
- Singhal, Sweety,Jain, Suman L.,Sain, Bir
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p. 620 - 621
(2008/12/21)
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- A mild, rapid and highly regioselective ring-opening of epoxides and aziridines with acetic anhydride under solvent-free conditions using ammonium-12-molybdophosphate
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A highly regioselective ring opening of epoxides and aziridines can be carried out efficiently with acetic anhydride to form the acetates of the corresponding 1,2-diols and 2-amino-alcohols, respectively, using ammonium-12-molybdophosphate (AMP) as a heterogeneous catalyst, at room temperature, in the absence of solvent.
- Das, Biswanath,Reddy, V. Saidi,Tehseen, Fouzia
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p. 6865 - 6868
(2007/10/03)
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- A cheap, simple, and versatile method for acetylation of alcohols and phenols and selective deprotection of aromatic acetates under solvent-free condition
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Acyclic and cyclic acetates of various alcohols and phenols were obtained in excellent yields under mild reaction conditions in the presence of a catalytic amount of sodium hydroxide under solvent-free conditions and microwave irradiation. Selective deprotection of acetate group from the corresponding phenolic compounds was carried out in the presence of LiClO4· 2H2O. Copyright Taylor & Francis, Inc.
- Rajabi, Fatemeh,Saidi, Mohammad R.
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p. 483 - 491
(2007/10/03)
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- Tributylphosphine-catalyzed ring-opening reaction of epoxides and aziridines with acetic anhydride
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Reactions of aziridines and epoxides with acetic anhydride catalyzed by an organophosphine provided the corresponding esters of β-amino alcohols and 1,2-diols in high yields, respectively.
- Fan, Ren-Hua,Hou, Xue-Long
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p. 4411 - 4413
(2007/10/03)
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- Zeolite catalyzed ring opening of epoxides to acetylated diols with acetic anhydride
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HY Zeolite is found to be a versatile catalyst for opening of epoxides to the corresponding acetylated 1,2-Diols with acetic anhydride in good yields.
- Ramesh,Niranjan Reddy,Venugopal,Subrahmanyam,Venkateswarlu
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p. 2599 - 2604
(2007/10/03)
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- Distannoxane-catalyzed selective acetylation of 3-chloropropane-1,2- diol: A convenient synthesis of enantiopure epichlorohydrin
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A distannoxane catalyst effects exclusive acetylation of the primary alcohol of 3-chloropropane-1,2-diol. This reaction provides a convenient access to enantiopure epichlorohydrin.
- Orita, Akihiro,Ito, Toshihide,Yasui, Yutaka,Otera, Junzo
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p. 1927 - 1929
(2007/10/03)
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- Lipase-Catalyzed Enantiomer Selective Hydrolysis of 1,2-Diol Diacetates
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Enantiomer selective hydrolysis of racemic 1,2-diol diacetates (rac-2a-h) was investigated by using the inexpensive commercial porcine pancreatic lipase.The hydrolysis proceeds with variable regioselectivity but with moderate to good enantioselectivity yielding a mixture of isomeric monoacetates (3a-h and 4a-h) and unchanged diacetate enantiomers (2a-h).Evidence was found that both monoacetates (3a-h and 4a-h) are formed with the same sense of enantiomer selectivity.
- Poppe, Laszlo,Novak, Lajos,Kajtar-Peredy, Maria,Szantay, Csaba
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p. 2211 - 2218
(2007/10/02)
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- Acyclic Analogs of Nucleosides. Synthesis of Hydroxyalkylbenzimidazoles and -Benzotriazoles
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Condensation of trimethylsilyl derivatives of benzimidazole and benzotriazole with alkylating agents in the presence of trimethylsilyl trifluoromethanesulfonate or SnCl4, or direct alkylation of the sodium salts of benzimidazole and benzotriazole, gives 1-(2,3-dihydroxypropyl)-, 1-(3-hydroxy-2-oxabutyl)-, 1-(3-hydroxymethyl-4-hydroxy-2-oxabutyl)-, and 1-(1,5-dihydroxy-3-oxapent-2-yl)benzimidazole and -benzotriazole.
- Yavorskii, A. E.,Stetsenko, A. V.,Zavgorodnii, S. G.,Florent'ev, V. L.
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p. 163 - 167
(2007/10/02)
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- Synthesis of Nitriles from Haloesters, Haloketones and Haloethers
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The action of NaCN on haloesters, haloketones and haloethers has been studied.Haloesters wherein halogen and ester functions are located on adjacent carbon atoms, do not furnish the corresponding nitriles, whereas those with halogen and ester functions not located on adjacent carbon atoms, furnish the corresponding nitriles in good yields.The presence of hydroxy or ether function on the carbon adjacent to primary halide bearing carbon atom does not interfere in the reaction with cyanide. δ-Haloketones are transformed to ketonitriles, γ-Haloketones are transformed to cyclopropyl ketones and epoxyhalides to epoxynitriles.
- Talekar, D. G.,Joshi, P. L.,Ramaiah, P.,Rao, A. S.
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p. 145 - 151
(2007/10/02)
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