- Studies of the complexes of the 4-cyanophenyl[bis(ethylsulfonyl)]methane and 4-cyanophenyl[bis(benzylsulfonyl)]methane C-acids and TBD and MTBD N-bases
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The 1:1 complexes of 4-cyanophenyl[bis(ethylsulfonyl)]methane (CHA) and 4-cyanophenyl[bis(benzylsulfonyl)]methane (CHB) with 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) and 7-methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene (MTBD) have been examined by ESI MS, s
- Binkowska, Iwona,Huczyński, Adam,Brzezinski, Bogumi?,Jarczewski, Arnold
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Read Online
- Ethyl lactate mediated thioacetalization of aldehydes at ambient temperature
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Dithioacetalization reactions of aldehydes with thiols/thiophenols have been successfully achieved at room temperature by employing the green, bio-based ethyl lactate as the reaction medium. By means of this sustainable approach, a class of dithioacetals has been acquired with high diversity and efficiency.
- Wan, Jie-Ping,Jing, Yanfeng,Liu, Yunyun
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p. 1302 - 1305
(2016/09/28)
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- Cyanuric chloride-catalyzed thioacetalization for organocatalytic synthesis of thioacetals
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The thioacetalization of aromatic aldehydes has been realized with broad diversity in the presence of various thiols and thiophenols using cyanuric chloride as an organocatalyst.
- Liu, Yaqin
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p. 679 - 682
(2016/05/09)
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- Synthesis in ionic liquids only: Access to α-oxo-γ-thio-esters via Mukaiyama coupling
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Ionic liquids are solvents general enough to conduct a multi-step process in organic synthesis. We show that both the preparation of starting materials (thioacetals and enoxysilane) as well as their coupling can be realized in such medium.
- Jebri, Khouloud,Mazières, Marie-Rose,Ballereau, Stéphanie,Ben Ayed, Ta?cir,Plaquevent, Jean-Christophe,Baltas, Michel,Guillen, Frédéric
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supporting information
p. 1353 - 1356
(2014/03/21)
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- Triflic acid catalyzed reductive coupling reactions of carbonyl compounds with O-, S-, and N-nucleophiles
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Highly efficient metal-free reductive coupling reactions of aldehydes and ketones with a range of nucleophiles in the presence of triflic acid (1-5 mol %) as the catalyst are presented. The reactions can be performed at ambient temperature without exclusion of moisture or air. A range of symmetrical and unsymmetrical ethers were obtained by this method in high yields and short reaction times. For the first time, the influence of additional functionalization has been studied. Furthermore, the formation of thioethers from ketones (by addition of unmodified thiols) and of sulfonamides from either aldehydes or ketones has been achieved under catalytic conditions.
- Gellert, Beate A.,Kahlcke, Nils,Feurer, Markus,Roth, Stefanie
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supporting information; experimental part
p. 12203 - 12209
(2011/11/07)
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- Silica-supported phosphorus pentoxide: A reusable catalyst for S,S-acetalization of carbonyl groups under ambient conditions
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Phosphorus pentoxide supported on silica gel (P2O 5/SiO2) efficiently acts as a highly active and reusable catalyst for cyclic and non-cyclic S,S-acetalization of a variety of carbonyl compounds under mild, solvent-free an
- Shaterian, Hamid Reza,Azizi, Kobra,Fahimi, Nafiseh
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experimental part
p. 85 - 91
(2012/01/06)
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- Catalytic syntheses of γ-functionalized α-keto esters from thioacetals and N,O-acetals
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Ethyl 2-(trimethylsilyloxy)acrylic ester (1a) reacts with thioacetals providing the corresponding α-keto-γ-thio esters in good to satisfactory yields. Whereas aminals do not react, N,O-acetals lead to γ-amino-α-keto esters in good to excellent yields. All reactions proceed under mild reaction conditions, and no additional work up is required. Subsequent transformations of the obtained products to the corresponding α-oximes have been demonstrated.
- Krebs, Anke,Bolm, Carsten
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experimental part
p. 4055 - 4060
(2011/06/24)
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- Silica-PCl5: A novel heterogenous catalyst for simple and efficient chemoselective protection of carbonyl compounds
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A simple, efficient and environmentally benign procedure has been developed for chemoselective protection of carbonyl compounds using the newly developed heterogeneous catalyst: Silica-PCl5. A variety of aldehydes and ketones were efficiently c
- Pandey, Lokesh Kumar,Pathak, Uma,Tank, Rekha,Mazumder, Avik
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experimental part
p. 167 - 171
(2010/07/05)
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- Hafnium trifluoromethanesulfonate (hafnium triflate) as a highly efficient catalyst for chemoselective thioacetalization and transthioacetalization of carbonyl compounds
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(Chemical Equation Presented) A range of carbonyl compounds including aliphatic and aromatic aldehydes and ketones were converted to the corresponding thioacetals in high yields in the presence of a catalytic amount of hafnium trifluoromethanesulfonate (0.1 mol %, room temperature). The mild conditions tolerated various sensitive functional and protecting groups and were racemization-free when applied to α-aminoaldehydes. Transacetalization and chemoselective thioacetalization of aromatic aldehydes in the presence of aliphatic aldehydes and ketones were also documented.
- Wu, Yan-Chao,Zhu, Jieping
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supporting information; experimental part
p. 9522 - 9524
(2009/04/06)
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- A simple and practical synthetic protocol for thioacetalization of carbonyl compounds
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Various aldehydes and ketones are smoothly converted to the corresponding acyclic and cyclic dithioacetals in very good yields by employing catalytic amount of acetyl chloride at room temperature under solvent-free conditions. Some of the major advantages of this procedure are its mild reaction conditions, highly efficient and selective, good yields, economically cheaper and compatible in the presence of a wide variety of other protecting groups.
- Khan, Abu T.,Mondal, Ejabul
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p. 844 - 850
(2007/10/03)
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- Proton Transfer from Carbon. A Study of the Acid-Base-catalysed Relaxation and the Bromination of Aryl-substituted Methanedisulfones
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Seven aryl-substituted derivatives of bis(ethylsulfonyl)methane have been synthesized and studied thermodynamically and kinetically in aqueous solution with respect to proton abstraction from the central carbon atom.The acidities of the six carbon acids are in the range pKA 10-12.The relaxation times of the reactions were studied by a spectrophotometric temperature-jump technique (hydroxide ion and phenolates as proton acceptors) and are in the microsecond range.The rates of bromination of the various carbanions have also been studied (potentiometrically) and the reactions are shown to be almost diffusion-controlled, with no marked trend with aromatic substituent.A small chemical activation may be due to a steric effect by the two sulfonyl groups.The rates of deprotonation, however, show considerable chemical activation, i.e., intrinsic rates are 3-4 orders of magnitude lower than for normal acids, indicating partial delocalization of the negative charge on the carbanion.This effect is somewhat larger than for cyano-activated carbon acids but considerably smaller than for carbon acids activated by carbonyl or nitro groups.It is concluded that sulfonyl groups interact with carbanions primarily by polar effects, but also, to some extent, mesomerically.The degree of mesomerism is, however, uncertain because part of the intrinsic barrier may derive from steric effects, as is also observed for bromination.
- Aiken, Fiona,Cox, Brian G.,Soerensen, Poul E.
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p. 783 - 790
(2007/10/02)
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