- Cyclopropenium Enhanced Thiourea Catalysis
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An integral part of modern organocatalysis is the development and application of thiourea catalysts. Here, as part of our program aimed at developing cyclopropenium catalysts, the synthesis of a thiourea-cyclopropenium organocatalyst with both cationic hydrogen-bond donor and electrostatic character is reported. The utility of the this thiourea organocatalyst is showcased in pyranylation reactions employing phenols, primary, secondary, and tertiary alcohols under operationally simple and mild reaction conditions for a broad substrate scope. The addition of benzoic acid as a co-catalyst facilitating cooperative Br?nsted acid catalysis was found to be valuable for reactions involving phenols and higher substituted alcohols. Mechanistic investigations, including kinetic and 1H NMR binding studies in conjunction with density function theory calculations, are described that collectively support a Br?nsted acid mode of catalysis.
- Smajlagic, Ivor,Durán, Rocio,Pilkington, Melanie,Dudding, Travis
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supporting information
p. 13973 - 13980
(2018/11/21)
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- Allyl tetrahydropyranyl ether: a versatile alcohol/thiol protecting reagent
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Allyl tetrahydropyranyl ether (ATHPE) can be used as a versatile protecting reagent. In combination with NBS/I2, O-allyl group can easily be replaced by hydroxyls (including tertiary-OH) or thiols, in the molecules comprising other reactive fun
- Kumar, Brijesh,Aga, Mushtaq A.,Mukherjee, Debaraj,Chimni, Swapandeep S.,Taneja, Subhash C.
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supporting information; experimental part
p. 6236 - 6240
(2010/01/18)
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- Efficient trimethylsilylation and tetrahydropyranylation of alcohols in the presence of 1,3-dibromo-5,5-dimethylhydantoin
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Chemoselective trimethylsilylation and tetrahydropyranylation of benzylic and primary and secondary aliphatic alcohols proceed efficiently in the presence of 1,3-dibromo-5,5-dimethylhydantoin (DBH) under mild and completely heterogeneous reaction conditio
- Shirini, Farhad,Zolfigol, Mohammad Ali,Paktinat, Maryam
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p. 4252 - 4256
(2008/03/27)
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- Efficient tetrahydropyranylation of alcohols and detetrahydropyranylation reactions in the presence of catalytic amount of trichloroisocyanuric acid (TCCA) as a safe, cheap industrial chemical
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Preparation and cleavage of THP ethers of different hydroxy functional groups are easily and efficiently performed in the presence of trichloroisocyanuric acid (TCCA) in the absence of solvent with high yields.
- Firouzabadi, Habib,Iranpoor, Nasser,Hazarkhani, Hassan
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p. 3623 - 3630
(2007/10/03)
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- Facile Tetrahydropyranylation of Alcohols and Phenols Using Anhydrous Calcium Chloride under Mild and Neutral Conditions
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Treatment of 3,4-dihydro-2H-pyran with various alcohols and phenols in the presence of a catalytic amount of anhydrous calcium chloride in dichloromethane furnished tetrahydropyranyl ethers under almost neutral conditions.
- Bandgar, Babasaheb P.,Sadavarte, Vaibhav S.,Uppalla, Lavkumar S.,Patil, Suresh V.
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p. 425 - 428
(2007/10/03)
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- Simple protocol for synthesis and cleavage of tetrahydropyranyl ethers using FeSO4 as an inexpensive catalyst
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Protection and deprotection of alcohols and phenols as tetrahydropyranyl ethers (THP ethers) using anhydrous FeSO4 under microwave irradiation without solvent is carried out.
- Bandgar, Babasaheb P.,Kasture, Suhas P.
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p. 877 - 878
(2007/10/03)
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- Iodine-Catalyzed Mild and Efficient Tetrahydropyranylation/Depyranylation of Alcohols
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Alcohols and phenols are tetrahydropyranylated rapidly in high yields in the presence of catalytic amount of iodine at room temperature. Depyranylation is effected readily by refluxing with iodine in methanol for few hours.
- Kumar, H. M. Sampath,Reddy, B. V. Subba,Reddy, E. Jagan,Yadav, J. S.
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p. 857 - 858
(2007/10/03)
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- Copper(II)chloride catalyzed tetrahydropyranylation of alcohols
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A simple and efficient methodology for the tetrahydropyranylation of alcohols using catalytic amount of copper(II)chloride in dichloromethane is described. The yields obtained are good to excellent.
- Bhalerao,Davis, K. Joju,Rao, B. Vittal
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p. 3081 - 3085
(2007/10/03)
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- Ceric ammonium nitrate catalysed protection of alcohols by 3,4-dihydro-2H-pyran
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Hydroxyl compounds readily add to dihydropyran in presence of a catalytic amount of ceric ammonium nitrate to give high yield of tetrahydropyranyl ethers.
- Maity,Roy
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p. 1667 - 1671
(2007/10/02)
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