ChemInform Abstract: One-Pot Synthesis of Carbohydrate Thionolactones from 1-Thiosugars (original) (raw)
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One-pot synthesis of carbohydrate thionolactones from 1-thiosugars
Tetrahedron Letters, 2008
A general and efficient one-pot method for the synthesis of carbohydrate thionolactones from the corresponding 1-thiosugar is described involving the formation of an intermediate glycosyl S-tert-butyl thiosulfinate in situ by treatment of a thiol with commercially available tert-butylsulfinyl chloride in toluene at room temperature, followed by thermolysis. The method can also be used to generate reactive thioaldehydes and thioketones directly
Synthesis of Thioglycosides by Tetrathiomolybdate-Mediated Michael Additions of Masked Thiolates
European Journal of Organic Chemistry, 2004
An efficient one-pot methodology for the synthesis of thioglycosides in excellent yields under neutral conditions through the use of benzyltriethylammonium tetrathiomolybdate [(BnNEt 3 ) 2 MoS 4 ; 1] as a sulfur-transfer reagent has been developed. The reagent 1 reacts with sugar halides to give sugar disulfides, which then undergo reductive cleavage in situ to provide the corresponding thiolates, followed by Michael addition to give the corresponding thioglycosides. most commonly used methods include the use of isothiourea derivatives of sugars (in turn derived from the glycosyl halides and thiourea) as precursors, treatment of glycosyl halides with thiolate anions, or the reaction between a 1thioglycopyranose and an alkyl halide. Other methods are based on Lewis acid catalyzed glycosylation of thiols. By this approach, thioglycosides have been prepared by starting from 1,2-trans-glycosyl esters, trichloroacetimid- [a] Further, the utility of this one-pot reaction in aqueous medium has been exemplified through the use of ammonium tetrathiomolybdate [(NH 4 ) 2 MoS 4 ; 2]. The application of this methodology has been extended to the synthesis of a variety of thiosugar analogues with excellent diastereoselectivity through inter-and intramolecular reactions.
Reaction of 1,2-trans-glycosyl acetates with thiourea: a new entry to 1-thiosugars
Tetrahedron Letters, 2003
The reaction of 1,2-trans-glycosyl acetates with thiourea under boron trifluoride etherate catalysis affording acetylated S-glycosyl isothiourea derivatives is described. The isothiourea derivatives obtained can be readily transformed into the desired 1-thiosugar derivative by reaction with triethylamine and subsequent alkylation or acylation of the in situ formed 1-thioaldose.
Solid-phase thiolsulfinates for the reversible immobilization of thiols
Applied Biochemistry and Biotechnology, 1994
A new method for the reversible immobilization of thiol-containing substances on agarose beads is presented. It is based on the use of thiolsulfinate (disulfide monoxide) as a solid-phase reactive group. The thiolsulfinate groups are introduced by controlled oxidation of thiol agarose. The method comprises two steps: First, mild oxidation of the agarose thiol groups to disulfide structures with potassium ferricyanide. Second, the oxidation of the so-formed agarose disulfide groups to thiolsulfinate groups by use of a stoichiometric amount of the oxidizing agent magnesium monoperoxyphtalate.
Tetrahedron: Asymmetry, 2002
2R,3R,4S)-3,4-Dihydroxy-2-[(R)-1,2-dihydroxyethyl]thiolane (1,4-anhydro-4-thio-D-mannitol), 1 has been prepared from methyl 4,6-O-benzylidene-aD -altropyranoside 2 in seven steps, the latter being readily available from commercial methyl aD -glucopyranoside.
A mild and highly convenient chemoselective alkylation of thiols using Cs2CO3–TBAI
Tetrahedron Letters, 2005
A mild and improved method for the synthesis of thioethers has been developed. In the presence of cesium carbonate, tetrabutylammonium iodide, and DMF, various alkyl and aryl thiols underwent S-alkylation to afford structurally diverse sulfides in high yield. Unprotected mercaptoalcohols and thioamines reacted chemoselectively at the sulfur moiety exclusively. An example of a one-pot, solid-phase synthesis of a thioether is also described.
Applications of Cyclic Sulfates of vic -Diols: Synthesis of Episulfides, Olefins, and Thio Sugars
Journal of Organic Chemistry, 1997
A new efficient and expeditious one-pot synthesis of thiiranes and olefins from cyclic sulfates of vic-diols is described. Opening of cyclic sulfates with potassium thioacetate or potassium thiocyanate followed by treatment with sodium methoxide led to episulfides. Olefins were obtained when potassium selenocyanate was used as nucleophile, and the obtained monoesters were treated with sodium borohydride. This method was applied to acyclic polyols derived from chiral glycerine, 1,2isopropylidenehexofuranoses with different subtituents at C-3, and dimethyl acetals derived from pentoses and hexoses. The methodology is highly versatile, and its applicability has been demonstrated by the synthesis of different 4-and 5-thiosugars by opening of the thiirane ring with sodium acetate or lithium aluminum hydride. Reduction with lithium aluminum hydride of the thiocyanate sulfate potassium salt obtained by the opening of cyclic sulfate with KSCN allowed the direct synthesis of 5-deoxy-4-thio-and 6-deoxy-5-thiosugars. Cyclic thiosugars with the sulfur atom in the ring are obtained by acidic hydrolysis of the 5-thiol derivatives of 1,2-O-isopropylidenehexofuranoses and 4-thiopentose dimethyl acetals. Using this method, an efficient synthesis of 5-thio-L-fucose as well as the synthesis of 2,5-dideoxy-4-thiofuranose is described.