- An efficient catalyst-free regio- and stereoselective ring-opening of epoxides with phenoxides using polyethylene glycol as the reaction medium
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A catalyst-free regio- and stereoselective ring-opening of epoxides with phenoxides has been carried out efficiently using polyethylene glycol as the reaction medium to form the corresponding β-aryloxyalcohols in high yields at room temperature.
- Das, Biswanath,Krishnaiah, Maddeboina,Thirupathi, Ponnaboina,Laxminarayana, Keetha
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- Asymmetric Transfer Hydrogenation of 1,3-Alkoxy/Aryloxy Propanones Using Tethered Arene/Ru(II)/TsDPEN Complexes
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A series of propanones containing combinations of aryloxy and alkoxy substituents at the 1- and 3-positions were reduced to the alcohols via asymmetric transfer hydrogenation using a tethered Ru(II)/TsDPEN catalyst. The enantioselectivities of the reductions reveal a complex pattern of electronic and steric effects which, when used in a matched combination, can lead to the formation of products of up to 68% ee (84:16 er) from this highly challenging class of substrate.
- Forshaw, Sam,Matthews, Alexander J.,Brown, Thomas J.,Diorazio, Louis J.,Williams, Luke,Wills, Martin
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supporting information
p. 2789 - 2792
(2017/06/07)
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- Silver nanoparticle-catalysed phenolysis of epoxides under neutral conditions: Scope and limitations of metal nanoparticles and applications towards drug synthesis
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Chemo- and regio-selective epoxide phenolysis is reported for the first time under neutral condition catalysed by silver nanoparticles. Other metal nanoparticles (e.g., Au, Pd, Cu, In, and Ru) are less effective. The choice of solvent is critical with 2-propanol being the best followed by DEF. Amongst various stabilisers used (surfactants, PEGs, tetra-alkylammonium halides) the tetra-alkylammonium halides are found to be the most effective (TBAF > TBAB > TBACl > TBAI). The role of the silver nanoparticles is envisaged as synchronous mode epoxide-phenol dual activation via a cooperative network of coordination, anion-π interaction, and hydrogen bond. The silver nanoparticles are recovered and reused for five consecutive times. The reaction has been used for the synthesis of propranolol and naftopidil as a few representative cardiovascular drugs.
- Seth, Kapileswar,Roy, Sudipta Raha,Kommi, Damodara N.,Pipaliya, Bhavin V.,Chakraborti, Asit K.
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p. 164 - 172
(2014/06/23)
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- An efficient catalyst for ring opening of epoxides with phenol and thiophenol under solvent-free conditions
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An efficient and rapid procedure for ring opening reaction of various epoxides with phenol and thiophenol derivatives was developed. The procedure can be obtained at room temperature under solvent-free condition in presence of (C4H12N2)2[BiCl6] Cl·H2O (1 mol %). This catalyst can be reused several times without significant loss of activity.
- Lu, Hong-Fei,Zhou, Jun-Tao,Cheng, He-Long,Sun, Lei-Lei,Yang, Fei-Fei,Wu, Run-Ze,Gao, Yu-Hua,Luo, Zhi-Bin
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p. 11174 - 11184
(2014/01/06)
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- Synergistic dual activation catalysis by palladium nanoparticles for epoxide ring opening with phenols
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Synergistic dual activation catalysis has been devised for epoxide phenolysis wherein palladium nanoparticles induce electrophilic activation via coordination with the epoxide oxygen followed by nucleophilic activation through anion-π interaction with the aromatic ring of the phenol, and water (reaction medium) also renders assistance through 'epoxide-phenol' dual activation.
- Seth, Kapileswar,Roy, Sudipta Raha,Pipaliya, Bhavin V.,Chakraborti, Asit K.
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supporting information
p. 5886 - 5888
(2013/07/25)
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- Chiral epoxides via borane reduction of 2-haloketones catalyzed by spiroborate ester: Application to the synthesis of optically pure 1,2-hydroxy ethers and 1,2-azido alcohols
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An enantioselective borane-mediated reduction of a variety of 2-haloketones with 10% spiroaminoborate ester 1 as catalyst is described. By a simple basic workup of 2-halohydrins, optically active epoxides are obtained in high yield and with excellent enantiopurity (up to 99% ee). Ring-opening of oxiranes with phenoxides or sodium azide is investigated under different reaction conditions affording nonracemic 1,2-hydroxy ethers and 1,2-azido alcohols with excellent enantioselectivity (99% ee) and in good to high chemical yield. 2011 American Chemical Society.
- Huang, Kun,Wang, Haiyang,Stepanenko, Viatcheslav,De Jesus, Melvin,Torruellas, Carilyn,Correa, Wildeliz,Ortiz-Marciales, Margarita
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supporting information; scheme or table
p. 1883 - 1886
(2011/06/20)
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- Bi(OTf)3-catalyzed regioselective ring opening of epoxides with phenols: Facile synthesis of 1,3-diaryloxy-2-propanols
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Substituted aryl oxiranes undergo the facile ring opening with phenols in the presence of catalytic amount of bismuth(III) triflate to afford 1,3-diaryloxy-2-propanols in excellent yields under mild conditions. Bismuth(III) triflate is relatively non-toxic, easy to handle and inexpensive, which makes this procedure particularly attractive for large scale synthesis. Copyright
- Kamal, Ahmed,Ahmed, Syed Kaleem,Sandbhor, Mahendra,Khan, Mohammed Naseer Ahmed,Arifuddin, Mohammed
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p. 1142 - 1143
(2007/10/03)
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- Highly regioselective ring opening of epoxides with polymer supported phenoxide and naphthoxide anions
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Amberlite IRA-400 supported phenoxide and naphthoxide anions are easily prepared. These polymer supported reagents that are highly air stable are used for the regioselective ring opening reactions of different epoxides to give aryl ether alcohols in high yields under mild reaction conditions.
- Tamami,Iranpoor,Rezaei
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p. 2789 - 2795
(2007/10/03)
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- Highly regioselective ring opening of oxiranes with phenoxides in the presence of β-cyclodextrin in water
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Highly regioselective ring opening of oxiranes to β-hydroxy ethers with phenoxides has been achieved in impressive yields in the presence of β-cyclodextrin as catalyst and water as solvent.
- Surendra,Krishnaveni, N. Srilakshmi,Nageswar,Rao, K. Rama
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p. 4994 - 4995
(2007/10/03)
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