34340-38-0Relevant academic research and scientific papers
Stereochemical dependence of the mechanism of deoxygenation, with lithium triethylborohydride, in 4,6-O-benzylidenehexopyranoside p-toluenesulfonates
Baer, Hans H.,Mekarska-Falicki, Miroslawa
, p. 3043 - 3052 (2007/10/02)
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.
Cycloaddition with Unsaturated Carbohydrates,III. - The Stereochemistry of the Diels-Alder Reaction with Hex-2-enopyranoside and Hex-2-enopyranosid-4-uloses
Gnichtel, Horst,Gumprecht, Claus,Luger, Peter
, p. 1531 - 1544 (2007/10/02)
The diene addition to ethyl 4,6-di-O-acetyl-2,3-dideoxy-α-D-erythro-hex-2-enopyranoside (1) formed only the α-D-manno adduct 2.With alkyl 2,3-dideoxy-α(β)-D-glycero-hex-2-enopyranosid-4-uloses 3a and b, the L- and D-erythro adducts 4a, b and 5a, b, respec
