- An indium-TMSCl promoted reaction of diphenyl diselenide and diorganyl disulfides with aldehydes: novel routes to selenoacetals, thioacetals and alkyl phenyl selenides
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The reactions of diphenyl diselenide and dialkyl disulfides with aldehydes in the presence of In-TMSCl have been investigated. Aliphatic aldehydes provide the corresponding selenoacetals and aromatic aldehydes lead predominantly to benzyl phenyl selenides
- Ranu, Brindaban C.,Saha, Amit,Mandal, Tanmay
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experimental part
p. 2072 - 2078
(2009/07/11)
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- Reactions of Sulfoxides with Magnesium Amides. Transformations of Sulfoxides into Sulfides, Dithioacetals and Vinyl Sulfides
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The reactions of sulfoxides with magnesium amides generated in situ from the reaction of ethylmagnesium bromide and seconday amines, such as diisopropylamine (DIPA) or 2,2,6,6-tetramethylpiperidine (TMP) in diethyl ether, were examined.Diaryl sulfoxides were heated with the diisopropylaminomagnesium reagent in diethyl ether to give the corresponding diaryl sulfides in 42-52percent yields.Sulfoxides bearing hydrogens at the α-position only(RSOCH2R1) reacted with the tetramethylpiperidinomagnesium reagent at room temperature to produce the corresponding dithioacetals (RSCHR1SR) in 47-86percent yields.The treatment of sulfoxides bearing hydrogens both at the α-and β-positions (RSOCHR1CHR2R3) with the magnesium amides at room temperature afforded the corresponding vinyl sulfides (RSCR1=CR2R3) in 52-72percent yields accompanying 2.3-27percent yields of the corresponding dithioacetals.The pathways leading to the products involving the formation of the sulfur-stabilized carbonium ion intermediates are discussed.
- Kobayashi, Kazuhiro,Kawakita, Masataka,Yokota, Kouichi,Mannami, Tohru,Yamamoto, Koji,et al.
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p. 1401 - 1408
(2007/10/02)
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- Chemoselective Protection of Aldehydes as Dithioacetals in Lithium Perchlorate-Diethyl Ether Medium. Evidence for the Formation of Oxocarbenium Ion Intermediate from Acetals
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Aldehydes and acetals were very efficiently converted to acyclic and cyclic dithioacetals in 5 M lithium perchlorate/diethyl ether (LPDE) medium at ambient temperature in high yields.Spectroscopic and other experimental evidences strongly suggest the formation of oxocarbenium ion intermediates from acetals in 5 M LPDE which subsequently reacted with thiols to give the dithioacetals.Under the same conditions ketones and their acetals also reacted, albeit very slowly compared to aldehydes and acetals, to yield dithioacetals.The difference in their reactivity was successfully employed in the chemoselective dithioacetalization of aldehydes and acetals in the presence of ketones and their acetals.The chemoselective dithioacetalization of keto aldehydes has been realized with the keto group remaining intact.The present method offers a convenient, efficient, and neutral medium for the deprotection of acetals to aldehydes and also the chemoselective protection of aldehydes to dithioacetals.
- Saraswathy, V. Geetha,Sankararaman, S.
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p. 4665 - 4670
(2007/10/02)
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- SYNTHESIS OF 2-METHYLPROPENYL SULFIDES AND THEIR OXYGEN AND NITROGEN ANALOGS
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Conditions were developed for the convinient preparative synthesis of 2-methylpropenyl sulfides and their oxygen and nitrogen analogs on the basis of reactions of thiols, alcohols, and lactams with isobutyraldehyde in excess of chlorotrimethylsilane.By-pr
- Turchaninova, L.P.,Shipov, A.G.,Korchevin, N.A.,Deryagina, E.N.,Baukov, Yu.I.,Voronkov, M.G.
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p. 1889 - 1892
(2007/10/02)
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- DIRECT CONVERSION OF CARBOXYLIC ACIDS AND CARBOXYLIC ESTERS INTO S,S'-DIPHENYL ACETALS AND PHENYL SULFIDES WITH THEXYLPHENYLTHIOBORANE
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Reaction of carboxylic acids with thexylphenylthioborane in methylene chloride at room temperature gives S,S-diphenyl acetals in high yields and carboxylic esters are converted into phenyl sulfides in the presence of zinc iodide under similar conditions.
- Kim, Sunggak,Kim, Sung Soo
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p. 1913 - 1916
(2007/10/02)
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- Synthesis of Aldehydes from Phenylthiotrimethylsilylmethane
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Phenylthiotrimethylsilylmethyl-lithium (4) reacts with alkyl halides to give 1-phenylthio-1-trimethylsilylalkanes (5), which can also be prepared by the addition of alkyl-lithium to 1-phenylthio-1-trimethylsilylethene (8), or from bis(phenylthio)acetals (11).The 1-phenylthio-1-trimethylsilylalkanes (5) can be converted into the corresponding aldehyde (15) by oxidation to the sulphoxide (13), thermal rearrangement, and hydrolysis of the resultant O-silyl thioacetal (14).
- Ager, David J.
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p. 1131 - 1136
(2007/10/02)
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