- Indium tribromide-catalyzed chemoselective dithioacetalization of aldehydes in non-aqueous and aqueous media
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Indium tribromide efficiently catalyzes the chemoselective dithioacetalization of aldehydes in the presence of ketones in dichloromethane. The catalyst is also active in water, which can be reused, in the same pot, for several times without any decrease in the yield of reaction. (C) 2000 Published by Elsevier Science Ltd.
- Ceschi,De Araujo Felix,Peppe
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- Green, catalyst-free thioacetalization of carbonyl compounds using glycerol as recyclable solvent
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We describe herein the use of glycerol as an efficient and a recyclable solvent in the thioacetalization of aldehydes and ketones. The catalyst-free reactions proceed easily using glycerol at 90 °C and the corresponding thioacetals were obtained in good to excellent yields. Glycerol was recovered and utilized for further thioacetalization reactions.
- Perin, Gelson,Mello, Luzia G.,Radatz, Cátia S.,Savegnago, Lucielli,Alves, Diego,Jacob, Raquel G.,Lenard?o, Eder J.
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- Cerium triflate: An efficient and recyclable catalyst for chemoselective thioacetalization of carbonyl compounds under solvent-free conditions
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A simple and efficient chemoselective thioacetalization of carbonyl compounds has been achieved using Ce(OTf)3 (10 mol-%) as a catalyst under solvent-free conditions. Advantages of the methodology include very short reaction times, excellent yi
- Kumar, Anil,Rao, M. Sudershan,Kameshwara Rao
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experimental part
p. 135 - 140
(2010/05/18)
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- A highly efficient carbon-sulfur bond formation reaction via microwave-assisted nucleophilic substitution of thiols to polychloroalkanes without a transition-metal catalyst
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An efficient carbon-sulfur bond formation reaction has been developed under microwave irradiation. This reaction affords a novel and rapid synthesis of thioacetals and sulfides under mild conditions. This method is particularly noteworthy given its experimental simplicity and high generality, and no transition-metal catalysts were needed under our conditions.
- Cao, Yi-Ju,Lai, Yuan-Yuan,Cao, Hong,Xing, Xiao-Ning,Wang, Xiang,Xiao, Wen-Jing
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p. 1529 - 1533
(2007/10/03)
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- Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 15. Generation of alkoxycarbonyl(sulfenyl)carbenes and their intramolecular insertion to give alkenyl sulfides
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A range of 18 alkoxycarbonyl sulfinyl phosphorus ylides 9 have been prepared and their behaviour upon flash vacuum pyrolysis (FVP) at 600 deg C examined. For R1 = H, Me and Et they lose Ph3PO and in some cases Ph3P to give mixtures of products including the alkenyl sulfides 10, the sulfides 11, the disulfides 12 and the thioesters 14. The alkenyl sulfides 10 most likely arise from intramolecular insertion of the alkoxycarbonyl sulfenyl carbenes resulting from loss off Ph3PO to produce β-lactones which then lose CO2 and this is supported by the results from 13C labelled ylides. Possible mechanisms for the formation of 11 and 14 are also presented and the feasibility of various steps has been examined by preparation and pyrolysis of the proposed intermediates. In contrast, pyrolysis of the ylides 9 where R1 = Ph and the tert-butoxycarbonyl ylides 30 leads mainly to complete fragmentation with loss of Ph3PO and benzyl alcohol or 2-methylpropan-2-ol and does not give any useful sulfur-containing products. Four alkoxy-carbonyl sulfonyl diazo compounds 33 have been prepared and in three cases they give the alkenyl sulfones 34 upon FVP at 400 deg C, probably by an intramolecular insertion and decarboxylation process analogous to the formation of 10 from 9. On the other hand the alkoxycarbonyl carbenes produced by FVP of the amino acid-derived diazo compounds 35 undergo alternative proocesses with no sign of β-lactone formation. Fully assigned 13C NMR data are presented for 13 of the ylides.
- Aitken, R. Alan,Armstrong, Jill M.,Drysdale, Martin J.,Ross, Fiona C.,Ryan, Bruce M.
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p. 593 - 604
(2007/10/03)
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- Aggregative activation and carbanion chemistry: Complex base deprotonation and directed functionalisation of dithioacetals
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Bis(phenylthio)methane and [1,3]-dithiane were efficiently deprotonated by the NaNH2-Et(OCH2CH2)2-ONa complex base. A marked behaviour difference was observed between the sodium carbanion of [1,3]-dithiane and the corresponding lithio-derivative. A 'radicaloid' mechanism is proposed to explain the results observed.
- Gros, Philippe,Hansen, Philippe,Caubere, Paul
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p. 15147 - 15156
(2007/10/03)
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- Generation, Some Synthetic Uses, and 1,2-Vinyl Rearrangements of Secondary and Tertiary Homoallyllithiums, Including Ring Contractions and A Ring Expansion. Remarkable Acceleration of the Rearrangement by an Oxyanionic Group
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A very general preparative method for homoallyllithiums consists of reductive lithiation of homoallylithiums consists of reductive lithiation of homoallyl phenyl sulfides by lithium 4,4'-di-tert-butylbiphenylide.The sulfides can be prepared by a variety o
- Mudryk, Boguslaw,Cohen, Theodore
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p. 3855 - 3865
(2007/10/02)
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- A Regiospecific Route to Conjugated Enones via α-Phenylthio Ketones
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2,5-Dimethylhex-4-en-3-one, E-6-methylhept-2-en-4-one, E-7-methyloct-4-en-3-one, ar-tumerone, and E-7-oxo-oct-5-enoic acid were synthesized regiospecifically via α-phenylthio ketones from bisphenylthio carbanions and aldehydes.
- Durman, John,Elliott, Jason,McElroy, Andrew B.,Warren, Stuart
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p. 1237 - 1244
(2007/10/02)
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- A General Procedure for Preparing α-Lithiosilanes. Generalization of the Peterson Olefination
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A particularly convenient method for the preparation of α-lithiosilanes consists of the reductive lithiation of diphenyl thioacetals or thioketals with lithium 1-(dimethylamino)naphthalenide, treatment of the resulting anion with trimethylsilyl chloride,
- Cohen, Theodore,Sherbine, James P.,Matz, James R.,Hutchins, Robert R.,McHenry, Barry M.,Willey, Paul R.
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p. 3245 - 3252
(2007/10/02)
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