- A one-pot synthesis of 1,4-dithiins and 1,4-benzodithiins from ketones using the recyclable reagent 1,1′-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT)
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A novel access to 1,4-dithiins and 1,4-benzodithiins from the corresponding ketones in one-pot using the recyclable reagent, 1,1′-(ethane-1,2-diyl)dipyridinium bistribromide (EDPBT) is described. This method is mild, simple, environmentally benign and is
- Murru, Siva,Kavala, Veerababurao,Singh,Patel, Bhisma K.
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p. 1007 - 1011
(2008/02/04)
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- Stereoselective azide introduction during 1,2-sulfur migration in α-hydroxyalkyldithioacetals
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A series α-hydroxyalkyldithiolanes were reacted with a mixture of triphenylphosphine, diethyl azodicarboxylate and hydrazoic acid to give 2-azido-l,4-dithianes stereoselectively. Reduction of the azido group to an amine resulted in racemisation.
- Afonso, Carlos A. M.,Barros, M. Teresa,Maycock, Christopher D.
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p. 801 - 814
(2007/10/03)
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- Chemistry of ethanediyl S,S-acetals - 4. A promising way to cis-substituted olefins, stereoselectively from carbonyl compounds
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Aldehydes and methyl ketones readily afford 5,6-dihydro-1,4-dithiins that can be converted by n-butyllithium into their corresponding sulfur stabilized carbanions. Coupling of the latter with alkyl halides leads to species having a cis-configurated, disubstituted double bond tied up by the sulfur-containing ring which is known to be susceptible of selective removal.
- Caputo,Ferreri,Isita,Longobardo,Mastroianni,Palumbo
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p. 1345 - 1350
(2007/10/02)
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- Synthesis of 2,3-dihydro-1,4-dithiins and 2-alkylidene-1,4-dithianes by 1,2-sulfur migration in 2-(1-hydroxyalkyl)-1,3-dithiolanes
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2,3-Dihydro-1,4-dithiins and the isomeric 2-alkylidene-1,4-dithianes were synthesized from 1,2-diketones and alkyl pyruvates by kinetically controlled ring expansion of 2-(1-hydroxyalkyl)-1,3-dithiolanes with p-toluenesulfonyl chloride in pyridine. In addition, 2,3-dihydro-1,4-dithiins, the thermodynamic products, were formed exclusively by using p-toluenesulfonic acid in refluxing benzene. The 2-alkylidene-1,4-dithianes were readily isomerised to the corresponding 2,3-dihydro-1,4-dithiins. Similarly, 2,3-dimethyl-6,7-dihydro-5H-1,4-dithiepine and (+)-2-methylene-3-methyl-1,4-diethiepane were obtained from 2-[(S)-1-hydroxyethyl]-2-methyl-1,3-dithiane.
- Afonso,Barros,Godinho,Maycock
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p. 575 - 580
(2007/10/02)
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