6748-86-3

Upstream product

• 98-59-9 p-toluenesulfonyl chloride 
• 71117-36-7 methyl 4,6-O-(S)-benzylidene-β-D-galactopyranoside 
• 1125-88-8 benzaldehyde dimethyl acetal 
• 1824-94-8 methyl beta-D-galactopyranoside 
• 28538-12-7 methyl 2-O-benzoyl-4,6-O-benzylidene-3-O-p-tolylsulfonyl-α-D-allopyranoside 
• 6698-34-6 methyl 4,6-O-benzylidene-3-O-p-tolylsulfonyl-α-D-allopyranoside 

Downstream Products

• 86420-78-2 methyl 2,3-anhydro-4,6-O-benzylidene-β-D-talopyranoside 
• 130272-53-6 methyl 4,6-O-benzylidene-2,3-dideoxy-β-D-threo-hex-2-enoside 
• 1385089-78-0 methyl 2,3-di-O-benzyl-4,6-O-benzylidene-β-D-idopyranoside 
• 1385089-80-4 methyl 2,3-di-O-benzyl-β-D-idopyranoside 
• 1385089-83-7 methyl 3-O-allyl-2-O-benzyl-4,6-O-benzylidene-β-D-idopyranoside 
• 1385089-86-0 methyl 3-O-allyl-2-O-benzyl-β-D-idopyranoside 
• 1385089-75-7 methyl 3-O-allyl-4,6-O-benzylidene-β-D-idopyranoside 
• 2880-96-8 methyl 2,3-anhydro-4,6-O-benzylidene-β-D-gulopyranoside 
• 1385089-67-7 methyl 3-O-benzyl-4,6-O-benzylidene-β-D-idopyranoside 
• 129831-96-5 methyl 4,6-O-(S)-benzylidene-3-O-methyl-β-D-idopyranoside 
• 1422739-66-9 methyl 4,6-O-benzylidene-3-deoxy-3-S-ethyl-β-D-idopyranoside 
• 4478-43-7 (1,2:3,4-di-O-isopropylidene-6-O-(p-toluensulfonate))-D-galactopiranose 
• 140-11-4 Benzyl acetate 
• 103-50-4 dibenzyl ether 

Relevant academic research and scientific papers

Evidence of cation-coordination involvement in directing the regioselective di-inversion reaction of vicinal di-sulfonate esters

Direct evidence has been obtained to confirm the unusual nucleophilic attack of an alkoxide at the S-center of sp3-hybridized sulfonyl esters. The unusual reaction pathway leads to S-O bond scission which is crucial for the regio- and stereoselective conversion of 2,3-di-O-sulfonates of 4,6-O-benzylidene-β-d-galactopyranosides into β-d-idopyranosides. In addition, strong evidence has been provided to clarify the role of the alkali counter-cation in the transformation. The cation is believed to influence the reaction rate via coordination to an oxygen in the sulfonate ester; the presence of a neighboring ring oxygen oriented in a cis-relationship greatly enhances reactivity of the sulfonyl ester.

A scalable approach to obtaining orthogonally protected β-d-idopyranosides

A practical method to obtain orthogonally protected d-idopyranose from d-galactose has been developed, which is the first method to enable synthesis of the challenging β-d-idopyranoside linkage. The method relies on a key double inversion at O-2 and O-3 in an easily prepared d-galactose derivative, which proceeds regio- and stereoselectively through a 2,3-anhydrotalopyranoside; reaction using a selection of alkoxides affords exclusively the 3-O-alkylidopyranoside, which can be used to generate an orthogonally protected monosaccharide. The process is scalable and requires minimal purification, so it could be used to produce building blocks to aid in the synthesis of various β-idopyranose-containing oligosaccharide targets to further probe their biological functions.

Stereochemical dependence of the mechanism of deoxygenation, with lithium triethylborohydride, in 4,6-O-benzylidenehexopyranoside p-toluenesulfonates

Lithium triethylborohydride was shown to react with methyl 4,6-O-benzylidene-α-D-hexopyranoside 2- and 3-tosylates, and 2,3-ditosylates, in the manno, allo, and altro configurational series both by O-S fission (O-desulfonylation) and by C-O fission (C-desulfonyloxylation), to produce carbinol and deoxy functions, respectively.The results were compared with those previously obtained with the corresponding gluco and galacto isomers, and the degree of facility of the cleavage reactions was seen to depend on the position of the sulfonic ester groups and the overall configuration of the molecules.The mechanism of reductive desulfonyloxylation also depended on configuration and was demonstrated to involve intermediary epoxide formation or displacement by internal hydride shift as the principal paths; competing elimination and direct nucleophilic displacement were found to occur in the allo series, whereas reduction accompanied by ring contraction has thus far been encountered only in the conformationally less constrained, cis-fused acetal system of the galacto series.Like the borohydride reagent, lithium aluminum hydride was found to react (though much more slowly) with the altro 2,3-ditosylate by the epoxide-mediated mechanism, although the latter hydride is known to desulfonyloxylate the α-D-gluco-isomer by a different, intramolecular reduction mechanism.

SELECTIVE ESTERIFICATION OF METHYL 4,6-O-BENZYLIDENE-α-D- AND β-D-GALACTOPYRANOSIDE IN A CATALYTIC TWO-PHASE SYSTEM

Selective tosylation of methyl 4,6-O-benzylidene-α-D- (1) and β-D-galactopyranoside (8) in a catalytic two-phase system (CTP system) yields preferentially 2-O-p-toluenesulfonate and 3-O-p-toluenesulfonate, respectively.In the course of unimolar benzoylation of 1 and 8, under similar conditions, a migration of the acyl group takes place and an equilibrium mixture is obtained.Esterification of 1 and 8 with benzoyl chloride under CTP conditions, in presence of an aqueous sodium hydroxide solution, saturated with sodium perchlorate, afforded in preponderant yields 2-O-benzoate and 3-O-benzoate, respectively.