- Dehydration reactions in water. Surfactant-type bronsted acid-catalyzed dehydrative etherification, thioetherification, and dithioacetalization in water
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Dehydration reactions such as etherification, thioetherification, and dithioacetalization are efficiently catalyzed by a surfactant-type Bronsted acid in water.
- Kobayashi, Shu,Iimura, Shinya,Manabe, Kei
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- Electrochemical Deprotection of para-Methoxybenzyl Ethers in a Flow Electrolysis Cell
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Electrochemical deprotection of p-methoxybenzyl (PMB) ethers was performed in an undivided electrochemical flow reactor in MeOH solution, leading to the unmasked alcohol and p-methoxybenzaldehyde dimethyl acetal as a byproduct. The electrochemical method removes the need for chemical oxidants, and added electrolyte (BF4NEt4) can be recovered and reused. The method was applied to 17 substrates with high conversions in a single pass, yields up to 92%, and up to 7.5 g h-1 productivity. The PMB protecting group was also selectively removed in the presence of some other common alcohol protecting groups.
- Green, Robert A.,Jolley, Katherine E.,Al-Hadedi, Azzam A. M.,Pletcher, Derek,Harrowven, David C.,De Frutos, Oscar,Mateos, Carlos,Klauber, David J.,Rincón, Juan A.,Brown, Richard C. D.
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p. 2050 - 2053
(2017/04/27)
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- Synthesis and properties of fluorous benzoquinones and their application in deprotection of silyl ethers
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1,4-Benzoquinone derivatives bearing trifluoromethyl, perfluorobutyl and perfluorohexyl groups were prepared and employed in the deprotection of silyl ethers. The fluorous character of these compounds was examined by measuring the partition coefficient between the fluorous and organic solvents. The benzoquinone derivatives showed significant fluorous character, indicating that they can be recovered from the reaction mixtures using a fluorous/organic biphasic system. The oxidising ability of the fluorous benzoquinones was estimated by cyclic voltammetry, and these compounds were found to be strong oxidisers. The fluorous benzoquinones were utilised in the oxidative desilylation of silyl ethers to afford the deprotected alcohols in high yield. In addition, the reduced fluorous benzoquinones were recovered from the reaction mixtures in good yields using a fluorous/organic biphasic system. This journal is the Partner Organisations 2014.
- Matsubara, Hiroshi,Maegawa, Takahiko,Kita, Yasuaki,Yokoji, Takato,Nomoto, Akihiro
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p. 5442 - 5447
(2014/07/21)
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- Selective synthesis of unsymmetrical ethers from different alcohols catalyzed by sodium bisulfite
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An efficient method for the preparation of unsymmetrical ethers from alcohols catalyzed by sodium bisulfite is reported. The procedure enables the direct dehydration of primary, secondary, and tertiary benzylic alcohols with aliphatic alcohols in the abse
- Yu, Jun-Lai,Wang, Hui,Zou, Kai-Feng,Zhang, Jia-Rui,Gao, Xiang,Zhang, Dan-Wei,Li, Zhan-Ting
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p. 310 - 315
(2013/01/15)
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- Dehydration reactions in water. Bronsted acid-surfactant-combined catalyst for ester, ether, thioether, and dithioacetal formation in water
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Dehydration reactions in water have been realized by a surfactant-type catalyst, dodecylbenzenesulfonic acid (DBSA). These reactions include dehydrative esterification, etherification, thioetherification, and dithioacetalization. In these reactions, DBSA and substrates form emulsion droplets whose interior is hydrophobic enough to exclude water molecules generated during the reactions. Detailed studies on the esterification revealed that the yields of esters were affected by temperature, amounts of DBSA used, and the substrates. Esters were obtained in high yields for highly hydrophobic substrates. On the basis of the difference in hydrophobicity of the substrates, unique selective esterification and etherification in water were attained. Furthermore, chemospecific, three-component reactions under DBSA-catalyzed conditions were also found to proceed smoothly. This work not only may lead to environmentally benign systems but also will provide a new aspect of organic chemistry in water.
- Manabe, Kei,Iimura, Shinya,Sun, Xiang-Min,Kobayashi, Shu
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p. 11971 - 11978
(2007/10/03)
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- PHOTOINDUCED SINGLE ELECTRON TRANSFER (SET) INITIATED OXIDATIVE CLEAVAGE OF BENZYLIC ETHERS PROTECTING GROUP: A MILD AND EFFICIENT PROCEDURE
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A very efficient and mild method for benzylic ether deprotection in neutral medium by photoinduced single electron transfer initiated oxidative cleavage is reported.
- Pandey, G.,Krishna, A.
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p. 2309 - 2314
(2007/10/02)
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