- Skeletal Rearrangement for Water Loss from Molecular Protonated Ions of t-Butoxycyclohexane
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Isotopic labelling and chemical substitution support the proposition that the skeletal rearrangement for water loss from molecular protonated ions of t-butoxycyclohexane involves competition between three reaction pathways.The principal reaction pathway (83percent) involves migration of the t-butyl group to the 2-(6-) position of the cyclohexyl ring with reciprocal hydrogen transfer.A second reaction pathway (12percent) involves ring contraction followed by reciprocal exchange of the t-butyl group with the 2-(5-) hydrogen atom of the nascent cyclopentyl ring.The third reaction pathway (5percent) involves rearrangement of a proton-bound complex to permit ipso attack by isobutene.Stereospecific substitutions indicate that the principal reaction pathway is susceptible to 1,3-diaxial interactions.
- Diakiw, Vladimir,Gordon, Patrick M.,Kingston, Eric E.,Shannon, James S.,Lacey, Michael J.
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- Zeolites Catalyze the Nazarov Reaction and the tert -Butylation of Alcohols by Stabilization of Carboxonium Intermediates
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Zeolites are the most used catalysts worldwide in petrochemistry processes, with particular ability to stabilize carbocations. However, the use of zeolites in organic synthesis is still scarce. We show here that representative carboxonium-mediated organic
- Blake, Finn,Leyva-Pérez, Antonio,Sanz-Navarro, Sergio,Tejeda-Serrano, María
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- METHOD FOR PRODUCING ASYMMETRIC ALKYL ETHER HAVING TERTIARY ALKYL GROUP
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PROBLEM TO BE SOLVED: To provide a method capable of obtaining an asymmetric alkyl ether having a tertiary alkyl group easily and industrially. SOLUTION: (1) There is provided a method for producing an asymmetric alkyl ether having a tertiary alkyl group by subjecting a tertiary alcohol and a primary alcohol or a secondary alcohol to a dehydration reaction using activated clay as a catalyst. (2) There is provided the method for producing an asymmetric alkyl ether having a tertiary alkyl group according to (1), where the tertiary alcohol is any one selected from the group consisting of tert-butanol, tert-amylalcohol and 1-adamantyl alcohol. SELECTED DRAWING: None COPYRIGHT: (C)2016,JPOandINPIT
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Paragraph 0028
(2017/01/31)
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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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- CATALYTIC C-H BOND ACTIVATION FOR THE SYNTHESIS OF ETHERS AND THIOETHERS
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Disclosed is a method for the transition metal-mediated oxidation of C-H bonds to form C-0 or C-S bonds. The methods are useful for the formation of ethers (R-OR') from alcohols, R'OH, and sp3 -hybridized C-H bonds in substrates, R-H. Aryl or heteroaryl acetates may also be used for C-H to C-OAr bond formation. The methods are also useful in the preparation of C-S bonds from acetyl-protected thiols, MeC(0)SR, and disulfides, RSSR. Advantageously, the methods minimize reaction steps, the handling of oxidized intermediates, and environmental impact.
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Page/Page column 54-59
(2014/01/08)
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- An efficient synthesis of tert-butyl ethers/esters of alcohols/amino acids using methyl tert-butyl ether
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A facile synthesis of a wide variety of tert-butyl ethers and tert-butyl ester derivatives under mild conditions is described. Alcohols etherified with tert-butyl methyl ether as tert-butyl source and solvent, in the presence of sulfuric acid. Many amino acid tert-butyl esters have been synthesized by this procedure. The reaction is simple, inexpensive, easily scaled up, and proceeds without observable racemization. A green method was developed for the deprotection of this group using Amberlite resin IR 120-H as catalyst.
- Mallesha,Prahlada Rao,Suhas,Channe Gowda
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experimental part
p. 641 - 645
(2012/02/15)
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- An eco-sustainable erbium(III) triflate catalyzed formation and cleavage of tert -butyl ethers
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An eco-compatible method, which permits the formation or cleavage of tert-butyl ethers of alcohols and phenols, is proposed. The protection step is performed in solvent-free conditions at room temperature using catalytic amount of Er(OTf)3. The catalyst is easily- recovered from the aqueous phase and reused several times without significant loss of activity. The deprotection step developed is also highly eco-friendly since the tert-butyl group is removed very quickly from alcohols and phenols in methanol using MW irradiation-. Georg Thieme Verlag Stuttgart · New York.
- Procopio, Antonio,Costanzo, Paola,Curini, Massimo,Nardi, Monica,Oliverio, Manuela,Paonessa, Rosina
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experimental part
p. 73 - 78
(2011/03/19)
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- Saccharin sulfonic acid catalyzed N-Boc protection of amines and formation of tertbutyl ethers from alcohols
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Saccharin sulfonic acid (SaSA), as a stable reagent is easily prepared by the reaction of saccharin with neat chlorosulfonic acid at room temperature. This compound is able to catalyze conversion of amines to their corresponding N-Boc protected amines with (Boc)2O. Alcohols were also converted to their corresponding tert-butyl ethers. All reactions took place under mild conditions giving the desired products in good to high yields.
- Shirini,Zolfigol,AbediniM.
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experimental part
p. 603 - 607
(2010/10/21)
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- A new, practical and efficient method for protecting alcohols as tert-butyl ethers
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A new method for protecting alcohols as tert-butyl ethers is reported. The reaction is performed in tert-butyl acetate in the presence of a catalytic amount of HClO4. The process is extremely efficient and primary and secondary alcohols as well as diols are protected under very mild conditions. Remarkably, tert-butyl acetate can be easily recovered after the workup of the reaction and recycled.
- Barge, Alessandro,Occhiato, Ernesto G.,Prandi, Cristina,Scarpi, Dina,Tabasso, Silvia,Venturello, Paolo
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experimental part
p. 812 - 816
(2010/06/14)
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- Syntheses and conformational analyses of mono- and trans-1,4-dialkoxy substituted cyclohexanes-the steric substituent/skeleton interactions
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Mono- and trans-1,4-dialkoxy substituted cyclohexanes (alkyl=Me, Et, i-Pr, t-Bu) were prepared using the solvomercuration-demercuration (SM-DM) procedure. The axial?axial and axial,axial?equatorial, equatorial conformational equilibria of the products wer
- Kleinpeter, Erich,Thielemann, J?rg
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p. 9071 - 9081
(2008/02/09)
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- Solvomercuration-Demercuration. 12. The Solvomercuration-Demercuration of Olefins in Alcohol Solvents with Mercuric Trifluoroacetate--An Ether Synthesis of Wide Generality
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Studies on the solvomercuration-demercuration (SM-DM) of olefins in methyl, ethyl, isopropyl, and tert-butyl alcohols with mercuric trifluoroacetate have been extended. 1-Dodecene undergoes the SM-DM sequence with typical results for a monosubstituted olefin.Cyclopentene similarly exhibited behavior characteristic of a 1,2-disubstituted olefin in methanol, ethanol, and 2-propanol, giving high yields, >90percent of the corresponding ethers.However, in tert-butyl alcohol, the yields of ether were lower than normal and decreased somewhat with time. 2-Methyl-1-butene gives >90percent yields of the Markovnikov methyl ether.On the other hand, the yields of ethyl, isopropyl, and tert-butyl ethers are lower and decrease with time.Major improvements in yields, however, are possible by lowering the reaction temperature from room temperature to 0 deg C.Cyclooctene, surprisingly, behaves more like a tri-, tetra-, or isosubstituted olefin than a 1,2-disubstituted olefin.The yields of cyclooctyl methyl ether are >90percent and do not decrease with time.However, yields of the ethyl, isopropyl, and tert-butyl ethers are lower and drop with time.Again, lowering the reaction temperature from room temperature to 0 deg C markedly improves the yields of the cyclooctyl ethers.These results, coupled with those of a previous study, clearly reveal the exceptional superiority of mercuric trifluoroacetate for the SM-DM of olefins in alcohol solvents.
- Brown, Herbert C.,Kurek, Joseph T.,Rei, Min-Hon,Thompson, Kerry L.
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p. 1171 - 1174
(2007/10/02)
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- Solvomercuration-Demercuration. 11. Alkoxymercuration-Demercuration of Representative Alkenes in Alcohol Solvents with the Mercuric Salts Acetate, Trifluoroacetate, Nitrate, and Methanesulfonate
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The alkoxymercuration-demercuration of seven representative olefins with the mercuric salts acetate, trifluoroacetate, nitrate, and methanesulfonate, in methyl, ethyl, isopropyl, and tert-butyl alcohols was examined.Mercuric acetate was effective only in methanol and ethanol.On the other hand, mercuric trifluoroacetate was effective in all four solvents, giving in most cases high yields of the corresponding ethers.Both mercuric nitrate and mercuric methanesulfonate were effective in methanol, ethanol, and 2-propanol.However, in several cases poor selectivity for the ether was observed, as evidenced by the formation of significant amounts of side products.Both electronic and steric effects are important factors in the reaction.Moreover, the structure of the olefin has a pronounced effect, both on the types of oxymercurials formed and on their stability to the reaction conditions.
- Brown, Herbert C.,Kurek, Joseph T.,Rei, Min-Hon,Thompson, Kerry L.
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p. 2551 - 2557
(2007/10/02)
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