1927-69-1Relevant academic research and scientific papers
Cyclopropenium Enhanced Thiourea Catalysis
Smajlagic, Ivor,Durán, Rocio,Pilkington, Melanie,Dudding, Travis
supporting information, p. 13973 - 13980 (2018/11/21)
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.
BiCl3: A versatile catalyst for the tetrahydropyranylation and depyranylation of 1°,2°,3°, allylic, benzylic alcohols, and symmetric diols
Vijaya Durga,Balamurali Krishna,Baby Ramana,Santha Kumari,Vijay,Hari Babu
, p. 1030 - 1034 (2017/05/26)
Bismuth trichloride as mild reagent, has been found to be a worthful catalyst for tetrahydropyranylation of 1°,2°,3°, allylic, benzylic alcohols, and symmetric di-ols. At room temperature the reagent THP(3,4-dihydro-2H-pyran) was successfully employed as pyranylating agent in presence of BiCl3catalyst without the use of a solvent and the yields of the products were found to be 90-96%. Further, the depyranylation of alcohols was achieved in quantitative yield by simple addition of MeOH using the same catalyst. The developed method was showed good chemo-selectivity in symmetrical diols for mono THP protection.
Tetrahydropyranylation of alcohols and phenols catalyzed by a new multi-wall carbon nanotubes-bound tin(IV) porphyrin
Gharaati, Shadab,Kargar, Hadi,Falahati, Ali Mohammad
, p. 1169 - 1178 (2017/05/15)
Abstract: In the present study, tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) using tetrakis(p-aminophenyl)porphyrinatotin(IV) trifluoromethanesulfonate, [SnIV(TNH2PP)(OTf)2], and tetrakis(p-aminophenyl)porphyrinatotin(IV) tetrafluoroborate, [SnIV(TNH2PP)(BF4)2], supported on multi-wall carbon nanotubes as new catalytic systems is investigated. These new catalysts, [SnIV(TNH2PP)(OTf)2@MWCNT] and [SnIV(TNH2PP)(BF4)2@MWCNT], were characterized using elemental analysis, FT-IR spectroscopic techniques, scanning electron microscopy and diffuse reflectance UV–Vis spectroscopic methods. In these catalytic systems, an optimization on the amounts of catalysts and amount of DHP was done in the tetrahydropyranylation of alcohols and phenols with DHP and the best outcomes were received in the presence of 0.01?mmol (40?mg) of [SnIV(TNH2PP)(OTf)2@MWCNT] and [SnIV(TNH2PP)(BF4)2@MWCNT] with 2?mmol of DHP. Efficiency and reusability are two important features of these new heterogenized catalysts for tetrahydropyranylation of primary, secondary and tertiary alcohols as well as phenols at room temperature. These catalysts were recovered several times with no loss on their initial activity, which indicates their high reusability and stability. Graphical Abstract: In the present study, tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) using tetrakis(p-aminophenyl)porphyrinatotin(IV) trifluoromethanesulfonate, [SnIV(TNH2PP)(OTf)2], and tetrakis(p-aminophenyl)porphyrinatotin(IV) tetrafluoroborate, [SnIV(TNH2PP)(BF4)2], supported on multi-wall carbon nanotubes as new catalytic systems is investigated. These new catalysts, [SnIV(TNH2PP)(OTf)2@MWCNT] and [SnIV(TNH2PP)(BF4)2@MWCNT], were characterized using elemental analysis, FT-IR spectroscopic techniques, scanning electron microscopy and diffuse reflectance UV–Vis spectroscopic methods. In these catalytic systems, an optimization on the amounts of catalysts and amount of DHP was done in the tetrahydropyranylation of alcohols and phenols with DHP and the best outcomes were received in the presence of 0.01?mmol (40?mg) of [SnIV(TNH2PP)(OTf)2@MWCNT] and [SnIV(TNH2PP)(BF4)2@MWCNT] with 2?mmol of DHP. Efficiency and reusability are two important features of these new heterogenized catalysts for tetrahydropyranylation of primary, secondary and tertiary alcohols as well as phenols at room temperature. These catalysts were recovered several times with no loss on their initial activity, which indicates their high reusability and stability. [Figure not available: see fulltext.].
Selective tetrahydropyranylation of alcohols and phenols using titanium(IV) salophen trifluoromethanesulfonate as an efficient catalyst
Yadegari, Maryam,Moghadam, Majid
, p. 872 - 875 (2016/09/20)
Titanium(IV) salophen trifluoromethanesulfonate, [TiIV(salophen)(OSO2CF3)2], as a catalyst enables selective tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran. Using this catalytic system, primary, secondary and tertiary alcohols, as well as phenols, were converted to their corresponding tetrahydropyranyl ethers in high yields and short reaction times at room temperature. Investigation of the chemoselectivity of this method showed discrimination between the activity of primary alcohols in the presence of secondary and tertiary alcohols and phenols. This heterogenized catalyst could be reused several times without loss of its catalytic activity. Copyright
Facile O-glycosylation of glycals using Glu-Fe3O4-SO3H, a magnetic solid acid catalyst
Thombal, Raju S.,Jadhav, Vrushali H.
, p. 30846 - 30851 (2016/04/09)
A new glucose derived magnetic solid acid catalyst (Glu-Fe3O4-SO3H) was synthesized in a convenient and ecofriendly manner and well characterized using FTIR, PXRD, EDAX, SEM, and XPS which showed the presence of Fe3/
An efficient Br?nsted–Lewis acidic ionic liquid catalyzed tetrahydropyranylation of alcohols
Azizi, Najmedin,Abdoli-Senejani, Masumeh,Abbasi, Faezeh
, p. 5009 - 5011 (2016/10/24)
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
Sulfonic acid-functionalized LUS-1: an efficient catalyst for tetrahydropyranylation/depyranylation of alcohols
Rahimifard, Mahshid,Mohammadi Ziarani, Ghodsi,Badiei, Alireza
, p. 6327 - 6336 (2016/07/06)
Efficient acidic functionalization of mesoporous silica LUS-1 (Laval University Silica) and its application as a recyclable heterogeneous catalyst for DHP (3,4-dihydro-2H-pyran) protection of alcohols and the subsequent removal of the corresponding protecting group have been reported. This green method offers a number of advantages such as short reaction time, good yields of protection and deprotection, simple work-up procedure, recyclable catalyst, and environmentally friendly conditions.
Tetrahydropyranylation of alcohols in the presence of a slightly basic, heterogeneous titanium catalyst
Magyar, ágnes,Nagy, Balázs,Hell, Zoltán
, p. 1876 - 1879 (2019/11/28)
4 ? molecular sieve modified with titanium (IV) is an efficient heterogeneous catalyst for the tetrahydropyranylation of alcohols under mild, slightly basic reaction conditions. The catalyst can be reused with good yield after a simple treatment with dichloromethane.
Highly efficient protection of alcohols and phenols catalysed by tin porphyrin supported on MIL-101
Zadehahmadi, Farnaz,Tangestaninejad, Shahram,Moghadam, Majid,Mirkhani, Valiollah,Mohammadpoor-Baltork, Iraj,Kardanpour, Reihaneh
, p. 209 - 215 (2015/03/30)
The catalytic activity of 5,10,15,20-tetrakis(4-aminophenyl)porphyrinatotin(IV) trifluoromethanesulfonate, [SnIV(TNH2PP)(OTf)2], supported on chloromethylated MIL-101, was investigated in the trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) and also their tetrahydropyranylation with 3,4-dihydro-2H-pyran. Excellent yields, mild reaction conditions, short reaction times and reusability of the catalyst without significant decrease in its initial activity are noteworthy advantages of this supported catalyst.
Short communication: Catalytic tetrahydropyranylation of phenols and alcohols using vanadium(V)-substituted polyoxomolybdates
Gharib, Ali,Jahangir, Manouchehr
experimental part, p. 287 - 296 (2012/05/20)
Alcohols and phenols were tetrahydropyranylated in the presence of H 7[PMo8V4O40] in good to excellent yields in acetonitrile and under solventfree reaction conditions. A mild and convenient method for the formation and deprotection of ethers (THP ethers) is described. The formation of THP ethers from the corresponding alcohols was accomplished in the presence of acid-sensitive functional groups.
