- 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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- Efficient Ring opening reaction of epoxides with oxygen nucleophiles catalyzed by quaternary onium salt
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Ring opening reactions of epoxides with oxygen nucleophiles catalyzed by a variety of quaternary onium salt, such as ammonium or phosphonium salt were explored. The results showed that tetrabutylphosphonium bromide (TBPB) among salts serves as the most ef
- Kim, Jin Won,Cho, Dae Won,Park, Gyoosoon,Kim, Sung Hong,Ra, Choon Sup
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p. 2286 - 2290
(2013/09/24)
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- 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2- diazaphosphorine supported on polystyrene (PS-BEMP) as an efficient recoverable and reusable catalyst for the phenolysis of epoxides under solvent-free conditions
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2-tert-Butylimino-2-diethylamino-1,3-dimethylperhydro-1,3, 2-diazaphosphorine supported on polystyrene (PS-BEMP) is an efficient catalyst for the ring-opening of epoxides with phenols (1.0 equiv.). Excellent yields have been obtained and in most of the cases the final products have been isolated in pure form without any additional purification step. E-factors associated to this protocol are small and further improvements were obtained by setting a cyclic continuous-flow reactor operating under solvent-free conditions (SolFC) that allowed us to minimize waste and reduce the E-factor by 95% compared to batch conditions. In addition the representative synthesis of a 2,3-dihydrobenzo[1,4]dioxepin-5-one has been realized. Optimization of this process was achieved by setting up an automated multi-step continuous-flow reactor based on a phenolysis process and a subsequent lactonization by thermal treatment of the reaction mixture. 3-Phenoxymethyl-2,3-dihydrobenzo[e][1,4] dioxepin-5-one was isolated in pure form and on a multi-gram scale in a very satisfactory 86% overall yield and an E-factor of 1.47.
- Zvagulis, Artis,Bonollo, Simona,Lanari, Daniela,Pizzo, Ferdinando,Vaccaro, Luigi
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supporting information; scheme or table
p. 2489 - 2496
(2010/12/29)
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- Erbium(III) triflate is a highly efficient catalyst for the synthesis of β-alkoxy alcohols, 1,2-diols and β-hydroxy sulfides by ring opening of epoxides
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Chemo- and stereoselectivity in the ring-opening reaction of epoxides with erbium(III) triflate are described. Epoxides can be cleaved under neutral conditions with alcohols and thiols in the presence of catalytic amounts of Lewis acid, affording the corresponding β-alkoxy alcohols and β-hydroxy sulfides in high yields. In water, epoxide ring opening occurs to produce the corresponding diols in good yields.
- Dalpozzo, Renato,Nardi, Monica,Oliverio, Manuela,Paonessa, Rosina,Procopio, Antonio
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experimental part
p. 3433 - 3438
(2010/02/28)
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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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- Silica sulfuric acid; an efficient and reusable catalyst for regioselective ring opening of epoxides by alcohols and water
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The nucleophilic ring opening reactions of epoxides by aliphatic alcohols and water are achieved efficiently in the presence of catalytic amounts of silica sulfuric acid with high degree of regioselectivity. The catalyst is reusable and can be applied several times without any decrease in the yield of reactions.
- Salehi, Peyman,Dabiri, Minoo,Zolfigol, Mohammad Ali,Fard, Mohammad Ali Bodaghi
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p. 1113 - 1121
(2007/10/03)
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- Magnesium hydrogensulfate: A cheap and efficient catalyst for the conversion of epoxides into β-alkoxy alcohols, vicinal-diols, and thiiranes
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The nucleophilic ring opening reactions of epoxides by aliphatic alcohols and water are achieved efficiently in the presence of catalytic amounts of magnesium hydrogensulfate, Mg(HSO4)2, with high degree of regioselectivity. The reactions are chemoselective and many of the other functional groups such as ethereal carbon oxygen bonds as well as carbon-carbon double bond remain intact under the reaction conditions. Epoxides also react with thiourea or ammonium thiocyanate in the presence of Mg(HSO 4)2 to afford the corresponding thiiranes in good to excellent yields.
- Salehi, Peyman,Khodaei, Mohammad Mahdi,Zolfigol, Mohammad Ali,Keyvan, Afsaneh
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p. 3041 - 3048
(2007/10/03)
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- Enantioselective parallel synthesis using polymer-supported chiral Co(salen) complexes
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(matrix presented) The kinetic resolution of epoxides with phenols catalyzed by a polymer-supported Co(salen) complex is applied to the first enantioselective catalytic synthesis of parallel libraries. The corresponding 1-aryloxy-2-alcohols are obtained i
- Peukert, Stefan,Jacobsen, Eric N.
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p. 1245 - 1248
(2008/02/09)
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- Organotin Phosphate Condensates as a Catalyst of Selective Ring-Opening of Oxiranes by Alcohols
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The highly regioselective alcoholysis of oxiranes is catalyzed by organotin phosphate condensates, providing a variety of β-alkoxy alcohols in good yields.The selectivity of the nucleophilic attack is dependent on the structures of epoxides.The gem-dialkyloxiranes are cleaved on the tertiary carbon, while β,γ-epoxy alcohols and their derivatives gave C-3 attack products.The anti stereoisomers are solely produced in the latter case.Thus the catalysis is both acidic and coordinative.Of practical importance is the recycled use of the catalyst without any appreciable decrease in the activity and the selectivities.
- Otera, Junzo,Niibo, Yoshihisa,Tatsumi, Naofumi,Nozaki, Hitosi
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p. 275 - 278
(2007/10/02)
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- HIGHLY REGIOSELECTIVE RING OPENING OF EPOXIDES WITH ALCOHOLS CATALYZED BY ORGANOTIN PHOSPHATE CONDENSATES
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Organotin phosphate condensates proved to catalyze the ring opening reaction of epoxides with alcohols in a highly regioselective manner.
- Otera, Junzo,Yoshinaga, Yukari,Hirakawa, Kazuhisa,Nakata, Tetsuya
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p. 3219 - 3222
(2007/10/02)
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