- Temporal control in tritylation reactions through light-driven variation in chloride ion binding catalysis-a proof of concept
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Tripodal triazole-linked azo(hetero)arene-based photoswitchable catalysts T1-5 have been designed, synthesized and optimized for the tritylation reaction of benzylamine (BzNH2). The tritylation reaction rates/yields achieved by light induced isomerization are compared between the native and photoswitched states of the catalyst T1. This concept of controlling the tritylation reaction rates with light has also been extended to additional substrates. The critical role of the triazole C-H?Cl- interactions has been confirmed by a combination of spectroscopic, calorimetric and computational studies. Also, the effect of variation in the binding affinities between the native and photoswitched states of the catalyst at room temperature in the temporal control of the catalysis has been demonstrated. This journal is
- Bari, Naimat K.,Grewal, Surbhi,Kumar, Himanshu,Roy, Saonli,Saraswat, Mayank,Sinha, Sharmistha,Venkataramani, Sugumar
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p. 7027 - 7033
(2020/11/09)
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- Nickel-Catalyzed Reductive Etherification of Aldehydes at Room Temperature: C-O vs C-C Bond Formation
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The reaction of secondary and tertiary benzyl alcohols activated by 2,4,6-trichloro-1,3,5-triazine (TCT) with aldehydes in the presence of NiCl2·dmg as a precatalyst in ethylene glycol afforded ethers at room temperature. A selective C-O vs C-C bond formation was observed for the secondary and tertiary benzyl alcohols in comparison with primary ones.
- Rahimi, Sajjad,Panahi, Farhad,Bahmani, Marzieh,Iranpoor, Nasser
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p. 973 - 979
(2018/01/27)
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- Stereoselective and Enantiospecific Mono- and Bis-C?H Azidation of Tr?ger Bases: Insight on Bridgehead Iminium Intermediates and Application to Anion-Binding Catalysis
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In the context of Tr?ger base chemistry, regio- and stereoselective Csp3?H azidation reactions are reported. Azide functional groups are introduced at either one or the two benzylic positions selectively. Mild conditions and good yields are aff
- Bosmani, Alessandro,Pujari, Sandip A.,Besnard, Céline,Guénée, Laure,Poblador-Bahamonde, Amalia I.,Lacour, Jér?me
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supporting information
p. 8678 - 8684
(2017/06/30)
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- Indium-mediated cleavage of the trityl group from protected alcohols and diols
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The reaction of primary, secondary, allylic and benzylic trityl ethers with indium powder in MeOH/NH4Cl led to reductive cleavage of the trityl-oxygen bond, affording the corresponding alcohols in good to excellent yield under very mild reaction conditions. The detritylation process could successfully be extended to mono and detritylated diols. This methodology represents a new and efficient detritylation procedure under mild reaction conditions.
- Behloul, Cherif,Chouti, Aicha,Guijarro, David,Foubelo, Francisco,Nájera, Carmen,Yus, Miguel
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p. 7937 - 7941
(2016/11/19)
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- Gold(I)-catalyzed synthesis of unsymmetrical ethers using alcohols as alkylating reagents
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A microwave-irradiated alcohol-protecting strategy based on gold catalysis utilizing benzyl alcohol, tert-butyl alcohol and triphenylmethanol as alkylating reagents has been developed. This protecting strategy has wide functional group tolerance with satisfactory yields for the majority of the selected alcohols. The mechanism of this transformation was probed with oxygen-18 isotope labelled alcohols assisted by GC-MS techniques and chemical kinetic experiments. This strategy provides an efficient, straightforward and alternative approach to the preparation of benzyl, tert-butyl and trityl ethers in organic synthesis.
- Liu, Yongxiang,Wang, Xiaoyu,Wang, Yanshi,Du, Chuan,Shi, Hui,Jin, Shengfei,Jiang, Chongguo,Xiao, Jianyong,Cheng, Maosheng
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p. 1029 - 1036
(2015/03/30)
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- Fe(III)-catalyzed trityl benzyl ether formation and disproportionation cascade reactions to yield benzaldehydes
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During investigating water-compatible Lewis acids catalyzed etherifications using alcohols as alkylating reagents directly, we developed Fe(III)-catalyzed trityl benzyl ether formations irradiated by microwave. Then an in situ trityl benzyl ether formation and disproportionation cascade reaction was achieved to yield the benzaldehyde products with good functional group tolerances under neat conditions at relative higher temperatures. The substituent effects of the substrates on the etherification and disproportionation were explored by changing the substitutions on benzyl alcohols and triarylmethanols using chemical kinetic plots methods and the mechanism of the transformation was studied by crossover experiments. The etherification and disproportionation cascade process could be conveniently scaled up in laboratory without losing much efficiency.
- Wang, Xiaoyu,Du, Chuan,Shi, Hui,Pang, Yadong,Jin, Shengfei,Hou, Yuqian,Wang, Yanshi,Peng, Xiaoshi,Xiao, Jianyong,Liu, Yang,Liu, Yongxiang,Cheng, Maosheng
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p. 6744 - 6748
(2015/08/24)
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- Highly efficient protection of alcohols as trityl ethers under solvent-free conditions, and recovery catalyzed by reusable nanoporous MCM-41-SO3H
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An efficient method was developed for the protection of alcohols as trityl ethers using triphenylmethanol in the presence of nanoporous MCM-41-SO3H as a heterogeneous catalyst under solvent-free ball-milling at room temperature. Low catalyst loading, high efficiency, reusability are among the advantages of this new solvent-free and environmentally friendly method. The deprotection of the produced trityl ethers was also efficiently achieved using the same catalyst in wet acetonitrile.
- Gholamzadeh, Zeynab,Naimi-Jamal, Mohammad Reza,Maleki, Ali
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p. 994 - 1001
(2015/01/09)
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- Iodine-catalyzed disproportionation of aryl-substituted ethers under solvent-free reaction conditions
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Iodine was demonstrated to be an efficient catalyst for disproportionation of aryl-substituted ethers under solvent-free reaction conditions. Variously substituted 1,1,1′,1′-tetraaryldimethyl ethers were transformed into the corresponding diarylketone and diarylmethane derivatives. I 2-catalyzed transformation of 4-methoxyphenyl substituted ethers yielded mono- and dialkylated Friedel-Crafts products as well. Treatment of trityl alkyl and trityl benzyl ethers with a catalytic amount of iodine produced triphenylmethane and the corresponding aldehydes and ketones. The electron-donating substituents facilitated the reaction, while the electron-withdrawing groups retarded it; the difference in reactivity is not very high. Such an observation may be in favour of hydride transfer, predominantly from the less electron rich side of the ether with more stable carbocation formation. With the isotopic studies it was established that a substantial portion of the C-H bond scission took place in the rate-determining step, while the carbonyl oxygen atom originated from the starting ether, and not from the air. The transformation took place under air and under argon, and HI was not a functioning catalyst.
- Jereb, Marjan,Vrazic, Dejan
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p. 1978 - 1999
(2013/05/22)
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- Zinc chloride homogeneous catalysis in the tritylation of hydroxyl- and amide-bearing molecules
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A tritylation protocol based on the transfer of the triphenylmethylcarbenium ion from trityl acetate to substrates having hydroxyls, in the presence of catalytic amounts of ZnCl2, is described. The advantages of this method are broad scope, mild conditions, and easy handling. The comparison with the procedure based on the use of equimolar mixture of TrCl and ZnCl2 in the presence of TEA shows that comparable results are obtained. However, only this method allows reactions of secondary or benzylic alcohols such as oxidation or formation of symmetric ethers to be suppressed. Both procedures are successfully extended to simple and substituted amides. Irrespective of its low solubility in acetonitrile, even asparagine can be directly tritylated on its amide group.
- Maltese, Maurizio,Vergari, Maria Cecilia,Donzello, Maria Pia
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supporting information; experimental part
p. 483 - 487
(2011/03/18)
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- A solvent free and selective method for preparation of triphenylmethyl ethers of alcohols and nucleosides
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A very simple and efficient method is described for protection of alcohols and nucleosides with trityl(triphenylmethyl), mono and dimethoxytrityl chlorides in the presence of triethylamine under microwave irradiation. High selectivity was observed for tritylation of 5'-OH function of nucleosides.
- Zekri, Negar,Alamdari, Reza Fareghi,Khalafi-Nezhad, Ali
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experimental part
p. 299 - 304
(2012/04/23)
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- FeCl3-catalyzed tritylation of alcohols in ionic liquids
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A simple and efficient protection of alcohols as trityl ethers is described using trityl chloride in the presence of 5mol% FeCl3 as catalyst in ionic liquids at room temperature in shorter reaction times. This mild and efficient method gives access to the
- Sreedhar,Radhika,Neelima,Chowdary,Rao, M. V. Basaveswara
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experimental part
p. 3785 - 3795
(2009/12/08)
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- Protecting groups transfer: Unusual method of removal of tr and TBDMS groups by transetherification
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The triphenylmethyl (Tr) group undergoes a transfer (transetherification or disproportionation) between the molecules of 5'-O-Tr-2'-deoxynucleosides in a process mediated by anhydrous sulfates of Cu+2, Fe+2, or Ni+2 to yield mixtures of 3',5'-bis-O-Tr and 3'-O-Tr products. If phenylmethanol is present in a reaction medium, detritylation results with concomitant formation of phenylmethyl triphenylmethyl ether. The behavior of t-butyldimethylsilyl (TBDMS) group in 5'-O-TBDMS-2'-deoxynucleosides is exactly the same. Such type of transetherifications was not observed before for the O-Tr and O-TBDMS groups. Copyright Taylor & Francis Group, LLC.
- Cabral, Nadia L. D.,Thiessen, Luciano Hoeltgebaum,Doboszewski, Bogdan
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p. 931 - 948
(2008/12/21)
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- Mild and adaptable silver triflate-assisted method for trityl protection of alcohols in solution with solid-phase loading applications
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Trityl ethers were prepared in solution in a matter of minutes by treating trityl chloride with silver triflate in the presence of alcohols. Yields were comparable or better than known literature methods. The method was compatible with the base-labile Fmo
- Lundquist IV, Joseph T.,Satterfield, Andrew D.,Pelletier, Jeffrey C.
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p. 3915 - 3918
(2007/10/03)
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- Detritylation Procedure under Non-Acidic Conditions: Naphthalene Catalysed Reductive Cleavage of Trityl Ethers
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The reaction of primary, secondary, allylic and benzylic trityl ethers 1 with lithium powder and a catalytic amount of naphthalene led to reductive cleavage of the trityl-oxygen bond, affording the corresponding alcohols 2 in good to excellent yields under very mild reaction conditions. The detritylation process could successfully be extended to several hydroxy, alkoxy and amino functionalised trityl ethers. This methodology represents a new and efficient detritylation procedure under non-acidic reaction conditions.
- Yus, Miguel,Behloul, Cherif,Guijarro, David
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p. 2179 - 2184
(2007/10/03)
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- Low-valent titanium mediated reductive cleavage of O/N-trityl bonds via free radical pathway
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Low-valent titanium mediated cleavage of trityl-O/N bonds in trityl ethers/amines via electron transfer process is reported. Chemoselective deprotection of trityl ethers in preference to benzyl ethers is achieved. The ease of cleavage of protected alcohols and amines is in the order O-allyl > O-trityl > O-benzyl; N-trityl > O-trityl bonds.
- Rele, Shyam,Nayak, Sandip K.
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p. 3533 - 3540
(2007/10/03)
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- Alkoxyallylsilanes: Functional protecting groups
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Allyl-t-butylmethylsilyl groups were shown to function as alcohol protecting groups whose hydrolytic stability was greater than t- butyldimethylsilyl (TBS) and Si(SiMe3)3 (sisyl) groups. Pseudo-first-order rate constants for the acid
- Balduzzi, Sonya,Brook, Michael A.
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p. 1617 - 1622
(2007/10/03)
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- Benzyl trityl ether and DDQ as new tritylating reagents
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We describe herein a new tritylation procedure of alcohols using benzyl trityl ether and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. The reaction involves oxidative abstraction of one of the benzylic protons of benzyl trityl ether, followed by transformation of the generated benzyl trityl ether cation into a complex of benzaldehyde and trityl cation. The present procedure proceeds under mild neutral conditions to afford trityl ethers in generally good yields for primary alcohols, and in acceptable yields for several secondary alcohols.
- Oikawa, Masato,Yoshizaki, Hiroaki,Kusumoto, Shoichi
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p. 757 - 760
(2007/10/03)
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- Convenient method for the preparation of trityl ethers from secondary alcohols
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The preparation of trityl ethers from secondary alcohols (10 mmol) with triphenylmethyl chloride (1.2 eq.) is carried out at room temperature by using DBU (1.4 eq.) as base in CH2Cl2. The high yielding procedure is very simple and it
- Colin-Messager, Sandrine,Girard, Jean-Pierre,Rossi, Jean-Claude
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p. 2689 - 2692
(2007/10/02)
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- C-Glycosides. 9. Stereospecific Synthesis of C-Glycosidic Spiroketal of the Papulacandins
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The reaction of ortho-lithiated triphenylmethyl benzyl ether with perbenzylated D-gluconolactone 1 followed by cyclization by BF3*Et2O provides a new stereospecific synthesis of C-glycosidic spiroketals.The structure of the peracetylated derivative was determined by X-ray diffraction.This methodology is applied to the synthesis of the spiroketal unit of papulacandins.
- Czernecki, Stanislas,Perlat, Marie-Claude
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p. 6289 - 6292
(2007/10/02)
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- Photolysis of 1,1,1,2-Tetraarylalkanes in the Presence of 1,4-Dicyanobenzene. A Photochemical C-C Bond Cleavage Reaction of Radical Cations in Solution
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Irradiation of acetonitrile-methanol (1:1) solutions of 1,1,1,2-tetraarylalkanes or 1,1,1-triphenyl-2-methoxyethane containing 1,4-dicyanobenzene led to the formation of triarylmethane and triarylmethyl methyl ethers in good yields.This C-C bond cleavage reaction is thought to proceed via a radical cation intermediate.
- Shi, Min,Okamoto, Yoshiki,Takamuku, Setsuo
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p. 1831 - 1840
(2007/10/02)
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- Regioselective N- or O-Tritylation of 2(1H)-Pyridone - (Triphenylmethyl)pyridones as Tritylation Agents
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Tritylation of 2(1H)-pyridone (1) with triphenylmethyl chloride (4) in acetonitrile leads exclusively to N-trityl-2(1H)-pyridone (3a) via the lithium salt 1', whereas 2-pyridyl trityl ether (3b) is the only product from the reaction with the sodium salt 1
- Effenberger, Franz,Brodt, Werner,Zinczuk, Juan
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p. 3011 - 3026
(2007/10/02)
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- SYNTHESIS AND CHARACTERIZATION OF 4-DIMETHYLAMINO-N-TRIPHENYLMETHYLPYRIDINIUM CHLORIDE, A POSTULATED INTERMEDIATE IN THE TRITYLATION OF ALCOHOLS
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4-Dimethylamino-N-triphenylpyridinium chloride (1) reacts with primary but not secondary alcohols to produce trityl ethers in good yield; in addition, amines may be selectively N-tritylated with 1 in the presence of alcohols.
- Hernandez, O.,Chaudhary, S. K.,Cox, R. H.,Porter, J.
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p. 1491 - 1494
(2007/10/02)
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