- Greener and regioselective ring opening of epoxides with TMSCN using potassium salts of magnetic carbon nitride
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Abstract: Potassium salts of magnetic graphitic carbon nitride (Fe3O4?g-C3N4-K) synthesized and proved to be a green and recyclable catalyst for rapid and regioselective ring opening of epoxides with TMSCN, yiel
- Azizi, Najmedin,Qomi, Mahnaz,Saadat, Mostafa
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p. 1597 - 1602
(2020/10/19)
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- Developing a Biocascade Process: Concurrent Ketone Reduction-Nitrile Hydrolysis of 2-Oxocycloalkanecarbonitriles
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A stereoselective bioreduction of 2-oxocycloalkanecarbonitriles was concurrently coupled to a whole cell-catalyzed nitrile hydrolysis in one-pot. The first step, mediated by ketoreductases, involved a dynamic reductive kinetic resolution, which led to 2-hydroxycycloalkanenitriles in very high enantio- and diastereomeric ratios. Then, the simultaneous exposure to nitrile hydratase and amidase from whole cells of Rhodococcus rhodochrous provided the corresponding 2-hydroxycycloalkanecarboxylic acids with excellent overall yield and optical purity for the all-enzymatic cascade.
- Liardo, Elisa,Ríos-Lombardía, Nicolás,Morís, Francisco,González-Sabín, Javier,Rebolledo, Francisca
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supporting information
p. 3366 - 3369
(2016/07/26)
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- Synthesis and characterization of a novel Fe3O4@SiO2/bipyridinium dichloride nanocomposite and its application as a magnetic and recyclable phase-transfer catalyst in the preparation of β-azidoalcohols, β-cyanohydrins, and
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β-Azidoalcohols, β-cyanohydrins, and β-acetoxy alcohols have been synthesized in the presence of a Fe3O4@SiO2/bipyridinium nanocomposite (Fe3O4@SiO2/BNC) as a novel magnetic and recyclable
- Kiasat, Ali Reza,Chadorian, Fatemeh,Saghanezhad, Seyyed Jafar
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p. 1297 - 1306
(2015/12/11)
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- Cytochrome P450 catalyzed oxidative hydroxylation of achiral organic compounds with simultaneous creation of two chirality centers in a single C-H activation step
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Regio- and stereoselective oxidative hydroxylation of achiral or chiral organic compounds mediated by synthetic reagents, catalysts, or enzymes generally leads to the formation of one new chiral center that appears in the respective enantiomeric or diastereomeric alcohols. By contrast, when subjecting appropriate achiral compounds to this type of C-H activation, the simultaneous creation of two chiral centers with a defined relative and absolute configuration may result, provided that control of the regio-, diastereo-, and enantioselectivity is ensured. The present study demonstrates that such control is possible by using wild type or mutant forms of the monooxygenase cytochrome P450 BM3 as catalysts in the oxidative hydroxylation of methylcyclohexane and seven other monosubstituted cyclohexane derivatives.
- Roiban, Gheorghe-Doru,Agudo, Ruben,Reetz, Manfred T.
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supporting information
p. 8659 - 8663
(2014/08/18)
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- Facile synthesis of an organic-inorganic nanocomposite, PEG-silica, by sol-gel method; Its characterization and application as an efficient catalyst in regioselective nucleophilic ring opening of epoxides: Preparation of β-azido alcohols and β-cyanohydrin
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The sol-gel method was used for the synthesis of a PEG-silica hybrid. In order to introduce PEG into the cavities of silica gel, first, the bis(3-trimethoxysilylpropyl)-polyethylene glycol precursor was synthesized by the reaction of 3-chloropropyltrimeth
- Kiasat, Ali Reza,Nazari, Simin,Davarpanah, Jamal
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p. 124 - 130
(2014/03/21)
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- Silica-bound 3-{2-[poly(ethylene glycol)]ethyl}-substituted 1-methyl-1H-imidazol-3-ium bromide: A recoverable phase-transfer catalyst for smooth and regioselective conversion of oxiranes to β-hydroxynitriles in water
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A series of β-hydroxynitriles were efficiently synthesized from the regioselective ring opening of oxiranes by cyanide anion in the presence of silica-bound 3-{2-[poly(ethylene glycol)]ethyl}-substituted 1-methyl-1H- imidazol-3-ium bromide (SiO2-PEG-ImBr) as a novel recoverable phase-transfer catalyst in H2O (Scheme 1 and Table 2). The workup procedure was straightforward, and the catalyst could be reused over four times with almost no loss of catalytic activity and selectivity. Copyright
- Reza Kiasat, Ali,Ayashi, Neda,Fallah-Mehrjardi, Mehdi
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p. 275 - 279
(2013/03/28)
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- An efficient [2 + 2 + 1] synthesis of 2,5-disubstituted oxazoles via gold-catalyzed intermolecular alkyne oxidation
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The first efficient intermolecular reaction of gold carbene intermediates generated via gold-catalyzed alkyne oxidation has been realized using nitriles as both the reacting partner and the reaction solvent, offering a generally efficient synthesis of 2,5-disubstituted oxazoles with broad substrate scope. The overall reaction is a [2 + 2 + 1] annulation of a terminal alkyne, a nitrile, and an oxygen atom from an oxidant. The reaction conditions are exceptionally mild, and a range of functional groups are easily tolerated. With complex and/or expensive nitriles, only 3 equiv could be sufficient to achieve serviceable yields in the absence of any solvent and using only 1 mol % BrettPhosAuNTf2 as the catalyst.
- He, Weimin,Li, Chaoqun,Zhang, Liming
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supporting information; experimental part
p. 8482 - 8485
(2011/07/08)
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- Ionic acylating agents for the enzymatic resolution of sec-alcohols in ionic liquids
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Potential acylating agents containing pendant ionic groups have been screened for the enzymatic kinetic resolution of rac-secondary alcohols in ionic liquids with CAL-B as biocatalyst. This study has allowed the identification of the 1-methyl-3-alkylimidazolium cation attached to a carboxylate group through a C10-alkyl chain as an efficient acylating agent for this transformation. This strategy was applied to the resolution of 2-hydroxycyclohexanecarbonitrile in which the 1R,2S enantiomer was isolated in 35 % ee (73 % yield) and the 1S,2R enantiomer in 97 % ee (23 % yield). Potential acylating agents containing pendant ionic groups have been screened for the enzymatic kinetic resolution of rac-secondary alcohols in ionic liquids with CAL-B as biocatalyst. This study has allowed theidentification of the 1-methyl-3-alkylimidazolium cation attached to a carboxylate group through a C10-alkyl chain as an efficient acylating agent for this transformation. Copyright
- Lourenco, Nuno M. T.,Monteiro, Carlos M.,Afonso, Carlos A. M.
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supporting information; experimental part
p. 6938 - 6943
(2011/02/24)
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- LiOH-catalyzed simple ring opening of epoxides under solvent-free conditions
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LiOH has been found to be a very simple and selective catalyst for the rapid and mild synthesis of β-hydroxy sulfides and β-hydroxyl nitriles by ring opening of epoxides with aromatic, aliphatic, and heterocyclic thiols and trimethylsilyl cyanide at room temperature under solvent free conditions. All the reactions proceeded satisfactorily in short times and afforded the corresponding products in good to excellent yields with high regioselectivity and chemoselectivity under mild reaction conditions. Copyright Taylor & Francis Group, LLC.
- Azizi, Najmedin,Khajeh-Amiri, Alireza,Ghafuri, Hossein,Bolourtchian, Mohammad
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experimental part
p. 1550 - 1557
(2010/09/06)
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- An environmentally benign catalytic method for efficient and selective nucleophilic ring opening of oxiranes by zirconium tetrakis(dodecyl Sulfate)
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An operationally simple and environmentally benign protocol for a highly regio- and chemoselective preparation of β-substituted alcohols by means of ring-opening reactions of oxiranes with various aliphatic alcohols, H 2O, NaN3 , and NaCN as nucleophiles in the presence of catalytic amounts of zirconium tetrakis(dodecyl sulfate) as Lewis acid/surfactant-combined catalysts (LASCs) was developed. The high efficiency of the catalyst was confirmed by the high product yields obtained within desired times and, in particularly by the reusability of the ZrIV complex.
- Jafarpour, Maasoumeh,Rezaeifard, Abdolreza,Aliabadi, Marzieh
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scheme or table
p. 405 - 413
(2010/05/19)
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- A chemoenzymatic synthesis of an androgen receptor antagonist
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A new scalable enzymatic resolution approach to both enantiomers of trans-2-hydroxycyclohexanecarbonitrile (9 and 11) was developed. Treatment of the racemic mixture (4) with succinic anhydride in the presence of Novozym 435 led to selective acylation of one enantiomer to the corresponding hemisuccinate, which was separated from the unreacted enantiomer by a simple basic extraction. This procedure produced the desired enantiomer in high ee, while obviating the need for chromatography or expensive catalysts and ligands. The application of this protocol to the large-scale synthesis of an androgen receptor antagonist (1) is described.
- Vaidyanathan, Rajappa,Hesmondhalgh, Lynsey,Hu, Shanghui
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p. 903 - 906
(2012/12/30)
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- Synthesis of β-hydroxy nitriles and 1,3-amino alcohols from epoxides using acetone cyanohydrin as a LiCN precursor
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The reaction of acetone cyanohydrin with MeLi affords a LiCNA·acetone complex that can be made to react with epoxides in THF, either in one-pot or using isolated samples of the cyanide complex, to cleanly afford β-hydroxy nitriles upon aqueous workup; in situ hydride reduction of nitriles affords 1,3-amino alcohols.
- Ciaccio, James A.,Smrtka, Michael,Maio, William A.,Rucando, David
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p. 7201 - 7204
(2007/10/03)
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- Micellar media for the efficient ring opening of epoxides with CN-, N3-, NO3-, NO2-, SCN-, Cl- and Br- catalyzed with Ce(OTf)4
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Micellar media are introduced for the efficient ring opening of epoxides with sodium salts of nucleophiles such as CN, N3-, NO3-, NO2, SCN, Br and Cl-, catalyzed with Ce(OTf)4. This method is an efficient procedure for the synthesis of different β-substituted alcohols under mild reaction conditions. The reaction with SCN- is an easy procedure for the high yielding preparation of epoxy sulfides.
- Iranpoor, Nasser,Firouzabadi, Habib,Shekarize, Marzieh
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p. 724 - 727
(2007/10/03)
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- Highly regioselective conversion of epoxides to β-hydroxy nitriles with cyanide exchange resin
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A simple and regioselective method is described for the efficient conversion of epoxides to β-hydroxy nitriles using Amberlite IRA-400 supported cyanide. The reactions occur in the absence of catalyst and furnish the corresponding β-hydroxy nitriles in high yields.
- Tamami,Iranpoor,Rezaei
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p. 3153 - 3157
(2007/10/03)
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- An Epoxide Ring-Opening Reaction via Hypervalent Silicate Intermediate: Synthesis of Statine
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The azide- and cyanide-opening reaction of epoxide with TBAF and TMSN 3 in THF or TBAF and TMSCN in MeCN occurred regioselectively to afford β-hydroxy azides and cyanides in good yield. These hypervalent silicates have been shown to be highly effective as nucleophilic azide and cyanide donors under mild conditions. This methodology has been applied to the preparation of statine.
- Konno, Hiroyuki,Toshiro, Emi,Hinoda, Naoyuki
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p. 2161 - 2164
(2007/10/03)
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- What about BOB? A synthetically useful protecting group
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Benzyloxybutyryl (BOB) esters of alcohols can be prepared from commercially available 4-benzyloxybutyric acid by standard acylation techniques, by the Mitsunobu reaction (with inversion of configuration), or by the Jacobsen asymmetric nucleophilic ring opening of epoxides. BOB esters can be removed selectively in the presence of other esters under conditions that are compatible with a variety of sensitive functional groups. (C) 2000 Elsevier Science Ltd.
- Clark,Ganem
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p. 9523 - 9526
(2007/10/03)
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- Ring Opening of Epoxides with Acetone Cyanohydrin Catalyzed by Lanthanoid(III) Alkoxides
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Ring opening of epoxide and aziridine with acetone cyanohydrin is promoted by a catalytic amount of lanthanoid(III) alkoxide to provide β-hydroxy nitrile and β-amino nitrile, respectively.
- Ohno, Hiroshi,Mori, Atsunori,Inoue, Shohei
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p. 975 - 978
(2007/10/02)
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- Facile conversion of epoxides to β-hydroxy nitriles under anhydrous conditions with lithium cyanide
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Functionalized epoxides are easily and efficiently converted to β-hydroxy nitriles in good yield with high regio- and stereoselectivity upon treatment with lithium cyanide in refluxing anhydrous THF. The conditions described permit a one-pot conversion of
- Ciaccio,Stanescu,Bontemps
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p. 1431 - 1434
(2007/10/02)
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- Easy Direct Stereo- and Regioselective Formation of β-Hydroxy Nitriles by Reaction of 1,2-Epoxides with Potassium Cyanide in the Presence of Metal Salts
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A simple efficient, anti stereoselective, and highly regioselective method for the synthesis of β-hydroxy nitriles by the direct opening of 1,2-epoxides with KCN in acetonitrile, in the presence of metal salts, is described.This new method appears to be competitive with the other methods previously reported. Key words: β-hydroxy nitriles; epoxide opening reactions; regioselectivity; catalysts.
- Chini, Marco,Crotti, Paolo,Favero, Lucilla,Macchia, Franco
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p. 4775 - 4778
(2007/10/02)
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- Reaction of cyanotrimethylsilane with oxiranes under Yb(CN)3 catalysis
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Reaction of R3Yb, prepared from YbCl3 and RLi, with Me3SiCN gives Yb(CN)3, which is a highly efficient catalyst for regio and stereoselective cleavage of an oxirane with Me3SiCN under mild conditions
- Matsubara, Seijiro,Onishi, Hitoshi,Utimoto, Kiitiro
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p. 6209 - 6212
(2007/10/05)
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- Sulfonylisoxazolines: Reliable Intermediates for the Preparation of β-Hydroxy Nitriles
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A series of six sulfonylisoxazolines, which were readily prepared via cycloaddition of benzenesulfonylcarbonitrile oxide to alkenes, were cleaved in 86-94percent yield to β-hydroxy nitriles by the action of excess 2percent Na-Hg0.The stereochem
- Wade, Peter A.,Bereznak, James F.
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p. 2973 - 2977
(2007/10/02)
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