- Chlorotrimethylsilane and Sodium Iodide: A Remarkable Metal-Free Association for the Desulfurization of Benzylic Dithioketals under Mild Conditions
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A novel metal-free process allowing the reductive desulfurization of various benzylic dithioketals to afford diarylmethane and benzylester derivatives with good to excellent yields is reported. At room temperature, this mild reduction process requires only the use of TMSCl and NaI in CH2Cl2 and tolerates a large variety of functional groups. (Figure presented.).
- Zhao, Guangkuan,Yuan, Ling-Zhi,Alami, Mouad,Provot, Olivier
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p. 2522 - 2536
(2018/05/14)
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- 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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- 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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- Facile deprotection of dithioacetals by using a novel 1,4-benzoquinone/cat. NaI system
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The combination of 1,4-benzoquinone and a catalytic amount of NaI was found to be effective for the deprotection of dithioacetals. The reactions proceeded efficiently under mild, near-neutral reaction conditions, producing a wide range of aryl and alkyl aldehydes and ketones generally in high yields with good functional group compatibility. The method developed therefore represents a general, facile, and highly applicable approach for deprotecting dithioacetals.
- Inamoto, Kiyofumi,Yamada, Tetsuya,Kato, Sei-Ichi,Kikkawa, Shoko,Kondo, Yoshinori
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p. 9192 - 9199
(2013/10/01)
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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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- 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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- GaCI3- and TiCl4-catalyzed insertion of isocyanides into a C-S bond of dithioacetals
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(Chemical Equation Presented) The insertion reaction of isocyanide into a C-S bond of dithioacetals is catalyzed by GaCl3 or TiCl4 to afford thioimidates containing an a-alkylthio group. Balanced thiophilicity of these Lewis acids is
- Tobisu, Mamoru,Ito, Sana,Kitajima, Aki,Chatani, Naoto
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supporting information; body text
p. 5223 - 5225
(2009/06/18)
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- Efficient method for thioacetalization of carbonyl compounds in the presence of a catalytic amount of benzyltriphenylphosphonium tribromide (BTPTB) under solvent-free conditions
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A variety of carbonyl compounds have been successfully converted to the corresponding thioacetal derivatives in good to excellent yields on reaction of carbonyl compounds with 1,2-ethanedithiole, 1,3-propanedithiol, and ethylthiol in the presence of a cat
- Hajipour, Abdol Reza,Pourmousavi, Seied A.,Ruoho, Arnold E.
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p. 2548 - 2566
(2008/12/22)
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- An efficient method for thioacetalization of carbonyl compounds in the presence of a catalytic amount of benzyltriphenylphosphonium tribromide under solvent-free conditions
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A variety of carbonyl compounds have been successfully converted to the corresponding thioacetal derivatives in good to excellent yields on the reaction of carbonyl compounds with 1,2-ethanedithiole, 1,3-propanedithiol, and ethanethiol in the presence of
- Hajipour, Abdol R.,Pourmousavi, Seied A.,Ruoho, Arnold E.
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p. 921 - 937
(2008/02/05)
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- A mild and chemoselective dithioacetalization of aldehydes in the presence of anhydrous copper (II) sulfate
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Various aldehydes have been protected with different thiols as dithioacetals with excellent yields using anhydrous copper sulfate as a mild and chemoselective catalyst. The reaction is carried out in a solvent and/or under solvent-free conditions. The transthioacetalization of oxyacetals into dithioacetals was also achieved in an excellent yield. Copyright Taylor & Francis Group, LLC.
- Moghaddam, Firouz Matloubi,Bardajee, Ghasem Rezanejade,Oskui, Afsane Arefi
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p. 1445 - 1450
(2007/10/03)
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- Simple, mild and efficient thioacetalization and transthioacetalization of carbonyl compounds and deprotection of thioacetals: Unique role of thiols in the selectivity of thioacetalization
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Silica supported sodium hydrogen sulfate (NaHSO4·SiO 2) has been employed for efficient thioacetalization and transthioacetalization of carbonyl compounds in CH2Cl2 at room temperature. Selectivity of thioacetalization was dependent on the thiols used for the conversion. The same catalyst was also found to be effective for deprotection of thioacetals in CH2Cl2-H2O at room temperature.
- Das, Biswanath,Ramu, Ravirala,Reddy, Majjigapu Ravinder,Mahender, Gurram
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p. 250 - 254
(2007/10/03)
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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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- Investigations towards the chemoselective thioacetaliztion of carbonyl compounds by using ionic liquid [bmim]Br as a recyclable catalytic medium
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The ionic liquid based on the 1-n-butyl-3-methylimidazolium cation has been prepared and used as an efficient catalytic medum for the chemoselective thioacetalization of carbonyl compounds. Furthermore, recycling and reuse of this ionic liquid medium has
- Kamal, Ahmed,Chouhan, Gagan
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p. 579 - 582
(2007/10/03)
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- Cobalt(II)chloride catalyzed chemoselective thioacetalization of aldehydes
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A mild and chemoselective dithioacetalization procedure for the protection of various aldehydes in the presence of catalytic amount of cobalt(II)chloride is described.
- De, Surya Kanta
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p. 1035 - 1036
(2007/10/03)
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- A simple and practical synthetic protocol for acetalisation, thioacetalisation and transthioacetalisation of carbonyl compounds under solvent-free conditions
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A wide variety of carbonyl compounds can be converted smoothly to the corresponding acetals on treatment with alcohols or diols and triethyl orthoformate in the presence of a catalytic amount of (bromodimethyl)sulfonium bromide at room temperature. Similarly, various carbonyl compounds can be transformed into the corresponding dithioacetals on reaction with thiol or dithiols at room temperature by employing the same catalyst without any solvent. Moreover, O,O-acetals can also be converted into the corresponding dithioacetals under identical conditions. Some of the major advantages are mild reaction conditions, a high degree of efficiency, compatibilty with other protecting groups and the lack of solvents, particularly for thioacetalisation. In addition, no brominations occur at the double bond or α to the keto position or even in the aromatic ring under these experimental conditions. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
- Khan, Abu T.,Mondal, Ejabul,Ghosh, Subrata,Islam, Samimul
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p. 2002 - 2009
(2007/10/03)
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- Pr(OTf)3 as an efficient and recyclable catalyst for chemoselective thioacetalization of aldehydes
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Praseodymium triflate has been found to be an efficient and recyclable catalyst for chemoselective protection of aldehydes.
- De, Surya Kanta
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p. 2837 - 2840
(2007/10/03)
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- Chemoselective thioacetalization and transthioacetalization of carbonyl compounds catalyzed by immobilized scandium(III) triflate in ionic liquids
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Immobilized scandium triflate [Sc(OTf)3] in ionic liquids has been found to be an extremely efficient and recyclable catalyst for the thioacetalization and transthioacetalization of both aromatic and aliphatic aldehydes. Significant rate acceleration and chemoselectivity was achieved by employing this catalytic system.
- Kamal, Ahmed,Chouhan, Gagan
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p. 3337 - 3340
(2007/10/03)
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- Nickel(II) chloride as an efficient and useful catalyst for chemoselective thioacetalization of aldehydes
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A wide variety of acyclic and cyclic dithioacetals can be prepared chemoselectively from the corresponding aldehydes by employing a catalytic amount of nickel(II) chloride in dry CH2Cl2-MeOH (5:1) at room temperature in good yields.
- Khan, Abu T.,Mondal, Ejabul,Sahu, Priti R.,Islam, Samimul
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p. 919 - 922
(2007/10/03)
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- Oxathioacetalization, thioacetalization and transthioacetalization of carbonyl compounds by N-bromosuccinimide: Selectivity and scope
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Efficient oxathioacetalization, thioacetalization and transthioacetalization of carbonyl compounds have been achieved in high yields employing N-bromosuccinimide as a catalyst.
- Kamal, Ahmed,Chouhan, Gagan,Ahmed, Kaleem
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p. 6947 - 6951
(2007/10/03)
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- Scandium triflate as a recyclable catalyst for chemoselective thioacetalization
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Scandium triflate [Sc(OTf)3] has been found to be an extremely efficient and recyclable catalyst for the addition of ethanethiol, 1,2-ethanedithiol and 1,3-propanedithiol to both aromatic and aliphatic aldehydes. In addition, by employing this catalyst, high chemoselective thioacetalization of carbonyl compounds has been achieved.
- Kamal, Ahmed,Chouhan, Gagan
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p. 1347 - 1350
(2007/10/03)
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- Catalysis by ionic liquids: Solvent-free efficient transthioacetalisation of acetals by molten tetrabutylammonium bromide
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Transthioacetalisation of acetals to dithioacetals by a solvent-free reaction with a thiol or dithiol catalyzed by molten tetrabutylammonium bromide was presented. Acetals were prepared by standard methods and were purified by distillation or chromatography. Tetrabutylammonium bromide in molten state was demonstrated to be an efficient and recyclable catalyst. The methodology offered improvements over other procedures in relation to yield of products, selectivity for acetal of aldehyde over that of ketone, and mildness of reaction conditions.
- Ranu, Brindaban C.,Das, Arijit,Samanta, Sampak
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p. 1520 - 1522
(2007/10/03)
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- TITANIUM TETRACHLORIDE, AN EFFICIENT AND CONVENIENT REAGENT FOR THIOACETALIZATION
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Aldehydes and ketones, when exposed to alkyl thiols or suitable alkane dithiols in presence of titanium tetrachloride, furnish near quantitative yields of the corresponding thioacetals.
- Kumar, Vijay,Dev, Sukh
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p. 1289 - 1292
(2007/10/02)
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