- Copper-Catalyzed Oxidative Acetalization of Boronic Esters: An Umpolung Strategy for Cyclic Acetal Synthesis
-
A protocol for the acetalization of boronic esters is described. The reaction is catalyzed by copper, and the conditions proved to be mild and were amenable to a variety of functional groups. We expanded the Chan-Lam coupling to include C(sp3) nucleophiles and converted them into corresponding acetals. This method allows for the orthogonal acetalization of substrates with reactive, acid-sensitive functional groups.
- Miller, Eric M.,Walczak, MacIej A.
-
p. 8230 - 8239
(2020/07/15)
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- Heterogeneous acidic catalysts for the tetrahydropyranylation of alcohols and phenols in green ethereal solvents
-
The application of heterogeneous catalysis and green solvents to the set up of widely employed reactions is a challenge in contemporary organic chemistry. We applied such an approach to the synthesis and further conversion of tetrahydropyranyl ethers, an important class of compounds widely employed in multistep syntheses. Several alcohols and phenols were almost quantitatively converted into the corresponding tetrahydropyranyl ethers in cyclopentyl methyl ether or 2-methyltetrahydrofuran employing NH4HSO4 supported on SiO2 as a recyclable acidic catalyst. Easy work up of the reaction mixtures and the versatility of the solvents allowed further conversion of the reaction products under one-pot reaction conditions.
- Azzena, Ugo,Carraro, Massimo,Modugno, Gloria,Pisano, Luisa,Urtis, Luigi
-
supporting information
p. 1655 - 1659
(2018/07/25)
-
- Magnetic Fe3O4@silica sulfuric acid nanoparticles promoted regioselective protection/deprotection of alcohols with dihydropyran under solvent-free conditions
-
Protection (and deprotection) of hydroxyl groups via tetrahydropyranylation was carried out effectively using a catalytic amount of Fe3O4 supported silica sulphuric acid nanoparticles (Fe3O4@SiO2@SO3H) under solvent-free conditions. The synthesized nanocatalyst was characterized by XRD, TEM, FT-IR etc. A wide range of tetrahydropyranylated alcohol derivatives were synthesized using this heterogeneous magnetic nanocatalyst within 10-20 min with high yields. In addition, tetrahydropyranyl ethers could also be deprotected to the parent alcoholic compounds in the presence of MeOH using the same catalyst. After completion of the reactions, the catalyst was easily separated from the reaction medium using an external magnet, which ameliorated the overall synthetic process. The catalyst was recovered and reused for five successive reactions without any appreciable loss in its activity. Mild reactions conditions, operational simplicity, solvent free conditions, high selectivity, easy recyclability of the magnetic nanocatalyst, and high yields can be considered as the advantageous features of our procedure.
- Rajkumari, Kalyani,Kalita, Juri,Das, Diparjun,Rokhum, Lalthazuala
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p. 56559 - 56565
(2017/12/27)
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- P4VPy–CuO nanoparticles as a novel and reusable catalyst: application at the protection of alcohols, phenols and amines
-
P4VPy–CuO nanoparticles were synthesized using ultrasound irradiations. Relevant properties of the synthesized nanoparticles were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Fourier transform infrared spectroscopy. After identification, the prepared reagent was used for the promotion of different types of protection reactions of alcohols, phenols and amines. Easy workup, short reaction times, excellent yields, relatively low cost and reusability of the catalyst are the striking features of the reported methods.
- Shirini, Farhad,Fallah-Shojaei, Abdollah,Abedini, Masoumeh,Samavi, Laleh
-
p. 1699 - 1712
(2016/07/27)
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- Supported N-propylsulfamic acid onto Fe3O4 magnetic nanoparticles as a reusable and efficient nanocatalyst for the protection/deprotection of hydroxyl groups and protection of aldehydes
-
N-propylsulfamic acid supported onto Fe3O4 magnetic nanoparticles (MNPs-PSA) as an efficient and magnetically reusable nanocatalyst has been reported for the tetrahydropyranylation/depyranylation of a wide variety of alcohols and phenols by changing the solvent medium. Also, the protection of aldehydes as acylals using Ac2O in the presence of catalytic amount MNPs-PSA in good to high yields at room temperature under solvent-free conditions is described. After completing the reaction, the catalyst was easily separated from the reaction mixture with the assistance of an external magnetic field and reused for several consecutive runs without significant loss of their catalytic efficiency.
- Rostami, Amin,Tahmasbi, Bahman,Abedi, Fatemeh
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p. 3689 - 3701
(2016/04/05)
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- An efficient Br?nsted–Lewis acidic ionic liquid catalyzed tetrahydropyranylation of alcohols
-
An imidazolium based Br?nsted–Lewis acidic ionic liquid has been shown to be an excellent catalyst and reaction medium for the tetrahydropyranylation of various alcohols in good to excellent yields with short reaction times. Selective protection of benzyl
- Azizi, Najmedin,Abdoli-Senejani, Masumeh,Abbasi, Faezeh
-
p. 5009 - 5011
(2016/10/24)
-
- Solvent-free acetylation and tetrahydropyranylation of alcohols catalyzed by recyclable sulfonated ordered nanostructured carbon
-
Rapid and practical green acetylation and tetrahydropyranylation routes of structurally diverse alcohols and phenols were applied under solvent-free reaction conditions providing excellent yields, using catalytic amounts of environmentally friendly sulfonated ordered nanoporous carbon (CMK-5-SO 3H). Non-toxic nature of the catalyst, its easy handling, recovery and reusability, and the absence of any solvent characterize the presented procedures as efficient methods. These procedures provide methods for the separation of the product by simple filtration.
- Zareyee, Daryoush,Alizadeh, Parastoo,Ghandali, Mohammad S.,Khalilzadeh, Mohammad A.
-
p. 713 - 721
(2013/07/26)
-
- Mild and efficient chemoselective tetrahydropyranylation of alcohols using bronsted acidic ionic liquid as catalyst under solvent-free conditions
-
A straightforward and efficient method for preparation of morpholinium bisulfate ([mroH]HSO4) as a novel acidic ionic liquid is reported. The application of this efficient and inexpensive acidic ionic liquid catalyst for tetrahydropyranylation of alcohols under mild and solvent-free conditions at room was investigated.
- Hajipour, Abdol R.,Nasresfahani, Zahra
-
experimental part
p. 1995 - 2006
(2012/06/04)
-
- Anhydrous FePO4 as a cost-effective and recyclable catalyst for tetrahydropyranylation and tetrahydrofuranylation of alcohols and phenols
-
In this article, a mild and efficient protocol for the tetrahydropyranylation and tetrahydrofuranylation of various aliphatic and benzylic alcohols and phenols into their corresponding THP and THF ethers (with 3,4-dihydro- 2H-pyran, DHP and 2,3-dihydrofuran, DHF) has been developed using a catalytic amount of anhydrous FePO4 at room temperature and relatively short reaction times in good to excellent yields.
- Behbahani, Farahnaz K.,Farahani, Mona
-
experimental part
p. 431 - 435
(2012/04/17)
-
- Solvent-free tetrahydropyranylation of alcohols catalyzed by amine methanesulfonates
-
A comparative study of tetrahydropyranylation of alcohols under various solvents or solvent-free conditions using different amine methanesulfonates as catalysts shows that tetrahydropyranyl ethers of alcohols are obtained under solvent-free conditions in good yields using catalytic amounts of triethylenediamine methanesulfonate, 1,6-hexanediamine methanesulfonate, diethylenetriamine methanesulfonate and pyridine methanesulfonate, respectively. The reaction occurs readily in short times at room temperature catalyzed by these catalysts, especially triethylenediamine methanesulfonate. Some of the major advantages of this procedure are that the catalysts are environmentally friendly, highly effective, and easy to prepare and handle. The reaction is also clean and needs no solvent, and the work-up is very simple.
- Wang, Rui,Sun, Mingzhu,Jiang, Heng
-
experimental part
p. 61 - 67
(2012/02/16)
-
- 1,6-Hexanediamine methanesulfonate: A mild and efficient catalyst for the tetrahydropyranylation of alcohols under solvent-free conditions
-
Various alcohols react with 3,4-dihydro-2 H-pyran under mild conditions using a catalytic amount of 1,6-hexanediamine methanesulfonate. It affords the corresponding tetrahydropyranyl ethers in good yields at a faster rate in the absence of solvent. Taylor & Francis Group, LLC.
- Wang, Rui,Jiang, Heng
-
experimental part
p. 171 - 176
(2012/01/05)
-
- Efficient tetrahydropyranyl and tetrahydrofuranyl protection/deprotection of alcohols and phenols with Al(OTf)3 as catalyst
-
A simple and efficient method for the conversion of alcohols and phenols into their corresponding THP and THF ethers at room temperature has been developed using 1 mol % aluminium triflate as catalyst. The deprotection reaction in the presence of methanol using Al(OTf)3 was equally successful and could be performed at ambient temperature in high yields.
- Williams, D. Bradley G.,Simelane, Sandile B.,Lawton, Michelle,Kinfe, Henok H.
-
experimental part
p. 4573 - 4576
(2010/07/05)
-
- AI(OTf)3 - A highly efficient catalyst for the tetrahydropyranylation of alcohols under solvent-free conditions
-
A simple and highly efficient method has been developed for the tetrahydropyranylation of alcohols by their reaction with 3,4-dihydro-2H-pyran (DHP) using a catalytic amount (0.01-1 mol%) of aluminium triflate under solvent-free conditions. The effect of various factors like temperature, amount of the catalyst, and molar ratio of substrates on the reaction conditions has also been studied. The comparative study of tetrahydropyranylation of benzyl alcohol using various catalysts including some reported ones shows the efficiency of this catalyst.
- Kamal, Ahmed,Naseer A Khan,Srikanth,Srinivasa Reddy
-
scheme or table
p. 1099 - 1104
(2009/03/11)
-
- Efficient and ecofriendly protocol for tetrahydropyranylation/ depyranylation of alcohols in the presence of tin(II) chloride dihydrate
-
A mild, efficient, and solvent-free protocol for tetrahydropyranylation of alcohols in the presence of a catalytic amount of SnCl2·2H2O is reported. Simple filtration of the reaction mixture through a short silica-gel pad gives the pure products in excellent yields. Depyranylation can also be achieved by adding methanol under similar reaction conditions. Copyright Taylor & Francis Group, LLC.
- Gogoi, Dipankoj,Baruah, Nabajyoti,Bez, Ghanashyam
-
p. 595 - 599
(2007/10/03)
-
- Silica triflate as a new, mild and efficient catalyst for tetrahydropyranylation of alcohols and deprotection of tetrahydropyranyl ethers
-
Silica triflate, a new stable derivative of silica gel, is easily prepared by the reaction of silica gel with trifluoromethanesulfonyl chloride. Silica triflate acts as a highly effective and reusable catalyst for tetrahydropyranylation of alcohols and deprotection of tetrahydropyranyl ethers under mild and completely heterogeneous reaction conditions.
- Shirini,Marjani,Nahzomi, H. Taherpour
-
p. 2235 - 2240
(2008/02/08)
-
- Generally applicable organocatalytic tetrahydropyranylation of hydroxy functionalities with very low catalyst loading
-
This paper presents the first acid-free, organocatalytic tetrahydropyran and 2-methoxypropene protection of alcohols, phenols, and other ROH derivatives utilizing privileged N,N′-bis[3,5-bis(trifluoromethyl)phenyl]thiourea and a polystyrene-bound analogue. The reactions are broadly applicably (also on preparative scale), in particular, to acid-sensitive substrates such as aldol products, hydroxy esters, acetals, silyl-protected alcohols, and cyanohydrins. The catalytic efficiency is truly remarkably with turnover numbers of 100,000 and turnover frequencies of up to 5700 h-1 at catalyst loadings down to 0.001 mol%. The computationally supported mechanistic interpretation emphasizes the hydrogen bond assisted heterolysis of the alcohol and concomitant preferential stabilization of the oxyanion hole in the transition state. Georg Thieme Verlag Stuttgart.
- Kotke, Mike,Schreiner, Peter R.
-
p. 779 - 790
(2008/01/03)
-
- Reaction of tetrahydropyranyl ethers with triethylsilyl trifluoromethanesulfonate-2,4,6-collidine combination: Speculation on the intermediate, efficient deprotection, and application to efficient ring-closing metathesis as a tether
-
The reaction of tetrahydropyranyl (THP) ethers with triethylsilyl trifluoromethanesulfonate (TESOTf)-2,4,6-collidine proceeded via collidinium salt intermediates to give the alcohol and 4-triethylsiloxybutanal in good yields. The structure of the intermediate was confirmed by 1HNMR and FAB-MS studies and by trapping it with EtOH. The reaction was applied for mild, efficient, and highly chemoselective deprotection method of THP ethers. The characteristic feature of the reaction is that the reaction conditions are weakly basic. Then, the reaction can proceed without affecting acid-labile protecting groups. Furthermore, the intermediates from alkenol-THP ether were trapped with other alkenols to give acyclic mixed acetals, which were subjected to efficient ring-closing metathesis by using the tetrahydropyranyl unit as a tether.
- Fujioka, Hiromichi,Okitsu, Takashi,Ohnaka, Takuya,Sawama, Yoshinari,Kubo, Ozora,Okamoto, Kazuhisa,Kita, Yasuyuki
-
p. 636 - 646
(2008/02/09)
-
- Ruthenium(III) acetylacetonate [Ru(acac)3] - An efficient chemoselective catalyst for the tetrahydropyranylation (THP) of alcohols and phenols under solvent-free conditions
-
A catalytic amount of ruthenium(III) acetylacetonate (2 mol%) [Ru(acac)3] enables solvent-free tetrahydropyranylation of different types of alcohols and phenols at ambient temperature in moderate to excellent yields. Notably, selective monoprotection of diols can be achieved chemoselectively. Furthermore, the catalyst could be recovered and reused if necessary.
- Varala, Ravi,Adapa, Srinivas R.
-
p. 1174 - 1179
(2007/10/03)
-
- Silica-supported perchloric acid (HClO4-SiO2): A versatile catalyst for tetrahydropyranylation, oxathioacetalization and thioacetalization
-
A simple and convenient synthetic protocol for the protection of hydroxyl group as tetrahydropyranyl ether as well as carbonyl functionality as oxathioacetal and thioacetal has been achieved using a catalytic amount of silica-supported perchloric acid und
- Khan, Abu T.,Parvin, Tasneem,Choudhury, Lokman H.
-
p. 2497 - 2502
(2008/02/03)
-
- Efficient and convenient procedure for protection of hydroxyl groups to the THP, THF and TMS ethers and oxidation of these ethers to their aldehydes or ketones in [BPy]FeCl4 as a low cost room temperature ionic liquid
-
Alcohols were converted to the corresponding THP, THF or TMS ethers in high to excellent yields in 1-n-butylpyridinium chloroferrate media as a stable and low cost room temperature ionic liquid. In addition, oxidation of these ethers to their aldehydes or ketones without any overoxidation reactions in this ionic liquid was also performed.
- Khosropour, Ahmad R.,Khodaei, Mohammad M.,Ghaderi, Sattar
-
p. 326 - 330
(2007/10/03)
-
- Solvent-free carbon-oxygen bond formation catalysed by CeCl 3·7H2O/NaI: Tetrahydropyranylation of hydroxy groups
-
An efficient and highly chemoselective method fo the protection of free hydroxy compounds with 3,4-dihydro-2H-pyran is reported. Since the deprotection of THP-ethers occurs very readily at room temperature, the successful use of this type of protecting group depends only upon how readily it can be introduced. For this we have examined the tetrahydropyranylation of alcohols and phenols catalysed by the CeCl3·7H2O/NaI system surface under solvent-free conditions. The reaction presents the advantage of being performable under extremely mild conditions by use of catalytic amounts of an interesting Lewis acidic system consisting of the CeCl3· 7H2O/NaI catalyst combination, which can be easily separated from the reaction mixture. The advantages of this procedure, which utilizes cheap and "lfriendly" reagents, over the previously reported ones are discussed. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Bartoli, Giuseppe,Giovannini, Riccardo,Giuliani, Arianna,Marcantoni, Enrico,Massaccesi, Massimo,Melchiorre, Paolo,Paoletti, Melissa,Sambri, Letizia
-
p. 1476 - 1482
(2007/10/03)
-
- A mild and efficient tetrahydropyranylation and detetrahydropyranylation of alcohols and phenols by VCl3
-
Vanadium chloride is found to be an efficient catalyst for the tetrahydropyranylation and detetrahydropyranylation of various alcohols and phenols, giving good yields at room temperature and short reaction times. 2005 Springer Science+Business Media, Inc.
- Narsimha Reddy,Sunil Kumar,Kumar,Srinivasulu,Thirupathi Reddy,Rajitha
-
p. 1371 - 1373
(2007/10/03)
-
- A mild and efficient method for tetrahydropyranylation and detetrahydropyranylation of alcohols and phenols by BiOClO4.xH 2O (or) BiONO3
-
A mild and efficient method for the protection of alcohols and phenols as tetrahydropyranyl ethers 3a-k and their deprotection at room temperature using BiOClO4.xH2O (or) BiONO3 as catalyst is described.
- Thirupathi Reddy,Narsimha Reddy,Sunil Kumar,Srinivasulu,Rajitha
-
p. 2396 - 2398
(2007/10/03)
-
- Tetrahydropyranylation and depyranylation of alcohols catalyzed by aqueous zinc tetrafluoroborate
-
Aqueous solution of zinc tetrafluoroborate as an effective catalyst for tetrahydropyranylation and depyranylation of alcohols has been described. Copyright Taylor & Francis, Inc.
- Islam, Samimul,Majee, Adinath,Khan
-
p. 1789 - 1793
(2007/10/03)
-
- Chemoselective tetrahydropyranylation of primary alcohols under freezing water pressure
-
A highly efficient environmentally friendly method for selective tetrahydropyranylation of primary alcoholic groups under pressure exerted by freezing water has been described.
- Boruwa, Joshodeep,Bhuyan, Ranjana,Gogoi, Naminita,Barua, Nabin C.
-
p. 331 - 334
(2007/10/03)
-
- A highly efficient synthetic protocol for tetrahydropyranylation/ depyranylation of alcohols and phenols
-
Bismuth(III) nitrate pentahydrate [Bi(NO3)3· 5H2O] is found to be an effective catalyst for both tetrahydropyranylation and depyranylation of alcohols and phenols. Some of the major advantages of this protocol are: non-aqueous workup, good yields, the involvement of a less-expensive and nontoxic catalyst, and compatibility in the presence of a large number of other protecting groups. Notably, isopropylidene, benzylidene, and thioacetal groups are also unaffected under the experimental conditions. Remarkably, a selective mono-protection of diols and primary alcohols can be achieved chemoselectively by employing the same catalyst. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
- Khan, Abu T.,Ghosh, Subrata,Choudhury, Lokman H.
-
p. 4891 - 4896
(2007/10/03)
-
- Simple and facile tetrahydropyranylation of alcohols by use of catalytic amounts of benzyltriphenylphosphonium tribromide
-
An efficient and mild system for protection of a variety of alcohols with 3,4-dihydro-2H-pyran (DHP) in the presence of catalytic amounts of benzyltriphenyl-phosphonium tribromide (BTPTB) (1) gives the corresponding tetrahydropyan ethers (ROTHP) in dichloromethane. The experimental procedure is simple, and the products are straightforwardly isolated in high to excellent yields. Copyright Taylor & Francis, Inc.
- Hajipour,Pourmousavi,Ruoho
-
p. 2889 - 2894
(2007/10/03)
-
- Lithium hexafluorophosphate-catalyzed efficient tetrahydropyranylation of tertiary alcohols under mild reaction conditions
-
Lithium hexafluorophosphate is found to be an efficient catalyst for the tetrahydropyranylation of tertiary alcohols with dihydropyran under mild reaction conditions.
- Hamada, Nao,Sato, Tsuneo
-
p. 1802 - 1804
(2007/10/03)
-
- Cupric sulfate pentahydrate (CuSO4·5H2O): A mild and efficient catalyst for tetrahydropyranylation/depyranylation of alcohols and phenols
-
Various alcohols and phenols can be smoothly converted to the corresponding THP ethers using 20 mol % CuSO4·5H2O under mild reaction conditions at room temperature. Some of the major advantages of this procedure are nonaqueous work-up, very good yields, less expensive catalyst and compatibility with other protecting groups.
- Khan, Abu T.,Choudhury, Lokman H.,Ghosh, Subrata
-
p. 7891 - 7894
(2007/10/03)
-
- Organoindate Room Temperature Ionic Liquid: Synthesis, Physicochemical Properties and Application
-
The combination of equimolar amounts of solid 1-n-butyl-3-methylimidazolium chloride (BMI*Cl) with solid indium trichloride affords the new room temperature and air stable ionic liquid BMI*InCl4 (mp -6 deg C). The major physicochemical properties (density
- Neto, Brenno A. da Silveira,Ebeling, Gunter,Goncalves, Reinaldo S.,Gozzo, Fabio C.,Eberlin, Marcos N.,Dupont, Jairton
-
p. 1155 - 1158
(2007/10/03)
-
- Efficient tetrahydropyranylation of alcohols and detetrahydropyranylation reactions in the presence of catalytic amount of trichloroisocyanuric acid (TCCA) as a safe, cheap industrial chemical
-
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
-
p. 3623 - 3630
(2007/10/03)
-
- A simple and efficient tetrahydropyranylation using N-bromosuccinamide
-
Tetrahydropyranylation of hydroxyl groups of alcohols and phenols has been achieved easily and efficiently using N-bromosuccinamide at room temperature.
- Das, Biswanath,Reddy, M. Ravinder,Ravindranath,Reddy, V. Saidi,Venkateshwarlu
-
p. 1711 - 1712
(2007/10/03)
-
- The use of basic resin in the preparation of tetrahydropyranyl derivatives of alcohols and phenols
-
A quick and efficient method for the preparation of tetrahydropyranyl (THP) derivatives of phenols and alcohols using a basic resin IRA-400 (iodide) is described.
- Chaturvedi, Devdutt,Kumar, Atul,Ray
-
p. 437 - 438
(2007/10/03)
-
- Zeolite-catalyzed environmentally friendly tetrahydropyranylation of alcohols and phenols
-
A simple and environmentally friendly tetrahydropyranylation of various alcohols and phenols at room temperature was elaborated by using a small pore size zeolite. The material is also suitable for the deprotection but with less efficiency.
- Hegedues, Adrienn,Vigh, Ilona,Hell, Zoltan
-
p. 4145 - 4152
(2007/10/03)
-
- A Highly Efficient and Chemoselective Synthetic Protocol for Tetrahydropyranylation/Depyranylation of Alcohols and Phenols
-
Various alcohols and phenols can be converted efficiently to the corresponding tetrahydropyranyl (THP) ethers in good yields using catalytic amounts of bromodimethylsulfonium bromide (0.005-0.02 equivalent) at room temperature. On the other hand, various THP ethers can also be deprotected to the parent alcoholic or phenolic compounds in CH2Cl2/ MeOH (5:2) by employing 0.05 equivalent of the same catalyst. Some of the major advantages of this procedure are its mild conditions, that it is highly selective and efficient, high yielding, and cost-effective, that it needs no solvent and is compatible with the presence of other protecting groups. Furthermore, no brominations occur at a double or triple bond, at an allylic position or even at an aromatic ring. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.
- Khan, Abu T.,Mondal, Ejabul,Borah, Ballav M.,Ghosh, Subrata
-
p. 4113 - 4117
(2007/10/03)
-
- Facile Tetrahydropyranylation of Alcohols and Phenols Using Anhydrous Calcium Chloride under Mild and Neutral Conditions
-
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.
-
p. 425 - 428
(2007/10/03)
-
- Bismuth triflate: An efficient catalyst for the formation and deprotection of tetrahydropyranyl ethers
-
The tetrahydropyranylation of alcohols under solvent-free conditions is efficiently catalyzed by bismuth triflate (0.1 mol %). The experimental procedure is simple and works well with a variety of alcohols and phenols. The catalyst is insensitive to air and small amounts of moisture, easy to handle and relatively nontoxic. The deprotection of THP ethers is also catalyzed by bismuth triflate (1.0 mol %). ( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).
- Stephens, Jacqueline R.,Butler, Phillip L.,Clow, Curtis H.,Oswald, Matthew C.,Smith, Russell C.,Mohan, Ram S.
-
p. 3827 - 3831
(2007/10/03)
-
- LiBF4: A mild and efficient catalyst for the tetrahydropyranylation of alcohols and their detetrahydropyranylation
-
Catalytic amount of lithium tetrafluoroborate in dry acetonitrile catalyzes an efficient tetrahydropyranylation of different types of alcohols to afford the corresponding tetrahydropyranyl ethers in high yields. Deprotection of tetrahydropyranyl ethers can also be achieved efficiently in the presence of lithium tetrafluoroborate in methanol. The chemoselectivity was observed in the protection of alcoholic function in the presence of phenolic function.
- Kazemi,Kiasat,Ebrahimi
-
p. 2483 - 2487
(2007/10/03)
-
- Microwave accelerated tetrahydropyranylation and detetrahydropyranylation of alcohols, phenols, and thiols catalyzed by hydrated zirconia
-
A solvent free and expeditious method for tetrahydropyranylation and detetrahydropyranylation of alcohols, phenols and thiols is described using hydrated zirconia and 3,4-dihydro-2H-pyran (DHP). A comparison of this microwave-accelerated reaction with conventional heating condition is also presented.
- Gajare, Anil S.,Sabde, Dhananjay P.,Shingare, Murlidhar S.,Wakharkar, Radhika D.
-
p. 1549 - 1555
(2007/10/03)
-
- Simple protocol for synthesis and cleavage of tetrahydropyranyl ethers using FeSO4 as an inexpensive catalyst
-
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.
-
p. 877 - 878
(2007/10/03)
-
- Tetrabutylammonium tribromide (TBATB)-promoted tetrahydropyranylation/depyranylation of alcohols
-
Alcohols are tetrahydropyranylated rapidly in high yields in the presence of a catalytic amount of TBATB in dichloromethane at room temperature. Depyranylation to their parent alcohol is achieved in quantitative yields by merely changing the solvent to methanol.
- Naik, Sarala,Gopinath, Rangam,Patel, Bhisma K
-
p. 7679 - 7681
(2007/10/03)
-
- Acetonyltriphenylphosphonium bromide and its polymer-supported analogues as catalysts in protection and deprotection of alcohols as alkyl vinyl ethers
-
Both acetonyltriphenylphosphonium bromide (ATPB, 1) and poly-p-styryldiphenylacetonylphosphonium bromide (A) were effective catalysts in the protection of alcohols as THP, THF, and EE ethers as well as the cleavage of THP, THF, and EE ethers to the corresponding alcohols. They could be applied to 1°, 2° and 3° alcohols, phenol and acid-labile alcohols. Both ATPB and catalyst A are excellent catalysts in the present study. It needed only 1×10-2-1.25×10-2 mol equiv. of the polymer-supported catalyst A in the reactions.
- Hon, Yung-Son,Lee, Chia-Fu,Chen, Rong-Jiunn,Szu, Ping-Hui
-
p. 5991 - 6001
(2007/10/03)
-
- Simple, facile and highly selective tetrahydropyranylation of alcohols using silica chloride
-
A simple and efficient process for tetrahydropyranylation of alcohols has been developed by reacting with dihydropyran at room temperature in presence of catalytic amount of silica chloride. The process is highly selective for monoprotection of the hydroxyl groups of symmetric diols.
- Ravindranath,Ramesh,Das
-
p. 1777 - 1778
(2007/10/03)
-
- Ionic liquids as recyclable reaction media for the tetrahydropyranylation of alcohols
-
A comparative study of the catalysed tetrahydropyranylation of 1-phenylethanol by p-toluenesulphonic acid (TsOH), pyridinium p-toluenesulphonate (PPTS) and triphenylphosphine hydrobromide (TPP.HBr) using 3,4-dihydro-2H-pyran in dichloromethane or in the i
- Branco, Luís C.,Afonso, Carlos A. M.
-
p. 4405 - 4410
(2007/10/03)
-
- Potassium dodecatangestocobaltate trihydrate (K5CoW12O40·3H2O): A mild and efficient catalyst for the tetrahydropyranylation of alcohols and their detetrahydropyranylation
-
A simple, mild and effective method for tetrahydropyranylation of a variety of alcohols and cleavage of their tetrahydropyranyl ethers at ambient temperature in the presence of K5CoW12O40·3H2O as the catalyst with high turnovers is described.
- Habibi, Mohammad H.,Tangestaninejad, Shahram,Mohammadpoor-Baltork, Iraj,Mirkhani, Valiollah,Yadollahi, Bahram
-
p. 2851 - 2853
(2007/10/03)
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- Protection of alcohols and phenols with dihydropyran and detetrahydropyranylation by ZrCl4
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Alcohols and Phenols are protected efficiently with dihydropyran(DHP) in the presence of catalytic amounts of zirconium tetrachloridein dichloromethane. Deprotection of THP-ethers is also afforded in a methanolic solution at room temperature.
- Rezai, Nasrin,Meybodi, Farhat Alsadat,Salehi, Peyman
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p. 1799 - 1805
(2007/10/03)
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- Microwave assisted catalytic protection and deprotection of alcohols with 3,4-dihydro-2h-pyran
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Protection of alcohols as their 2-tetrahydropyranyl ethers and their subsequent hydrolysis can be easily achieved through a microwave irradiated reaction catalysed by iodine.
- Deka,Sarma
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p. 4435 - 4441
(2007/10/03)
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- Stannous chloride dihydrate: A new catalyst for the tetrahydropyranylation of alcohols
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Catalytic Stannous chloride dihydrate in polar aprotic solvents like chloroform efficiently catalyse the tetrahydropyranylation of alcohols in a short time under mild conditions.
- Joju Davis,Bhalerao,Vittal Rao
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p. 1679 - 1686
(2007/10/03)
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- Acetonyltriphenylphosphonium bromide in organic synthesis: An extremely efficient catalyst for the protection and deprotection of alcohols as alkyl vinyl ethers
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Acetonyltriphenylphosphonium bromide (ATPB) was an extremely effective catalyst in the preparation of THP, THF, and EE ethers as well as cleavage of THP, THF, and EE ethers to the corresponding alcohols. It could be applied to 1°, 2°and 3°alcohols and phenol.
- Hon, Yung-Son,Lee, Chia-Fu
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p. 2389 - 2392
(2007/10/03)
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- A mild and efficient tetrahydropyranylation of alcohols
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Triphenylphosphine (TPP)-iodotrimethylsilane (TMSI) was found to be a convenient and highly effective catalyst for the tetrahydropyranylation of aliphatic and aromatic alcohols with dihydropyran in dichloromethane at ambient temperature.
- Cha, Kyung Hoi,Kang, Tae Won,Lee, Hong-Woo,Kim, Eung-Nam,Choi, Nam-Hee,Kim, Jung-Woo,Hong, Chung Il
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p. 2131 - 2136
(2007/10/03)
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