51385-13-8Relevant academic research and scientific papers
A scalable approach to obtaining orthogonally protected β-d-idopyranosides
Hevey, Rachel,Morland, Alizee,Ling, Chang-Chun
experimental part, p. 6760 - 6772 (2012/09/25)
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.
DESULFONYLOXYLATION OF SOME SECONDARY p-TOLUENESULFONATES OF GLYCOSIDES BY LITHIUM TRIETHYLBOROHYDRIDE; A HIGH-YIELDING ROUTE TO 2- AND 3-DEOXY SUGARS
Baer, Hans H.,Hanna, Hanna R.
, p. 19 - 42 (2007/10/02)
Lithium triethylborohydride (LTBH) reacts readily with p-toluenesulfonates of methyl 4,6-O-benzylidene-α-D-glucopyranoside (4) to give deoxyglycosides in >90percent yield.Thus, the 2,3-ditosylate (1) and the 3-monotosylate (2) thereof afford methyl 4,6-O-benzylidene-2-deoxy-α-D-ribo-hexopyranoside (7) in highly regio- and stereo-selective reactions that proceed via methyl 2,3-anhydro-4,6-O-benzylidene-α-D-allopyranoside (6), and the 2-monotosylate (8) of 4 gives the 3-deoxy-α-D-arabino isomer (12) of 7 via the corresponding 2,3-anhydro-α-D-mannopyranoside 11.In the series of the corresponding β anomers, the 3-monotosylate 14 and the 2-monotosylate 16 are similarly desulfonyloxylated, with equal ease, but furnish mixtures of regioisomeric deoxyglycosides, namely, the 3- and 2-deoxy-β-D-ribo derivatives 20 and 21, and the 2- and 3-deoxy-β-D-arabino derivatives 22 and 23, respectively.It could be shown that this difference is due to the failure of the intermediary, β-glycosidic epoxides 18 and 19 (the anomers of 6 and 11) to obey the Fuerst-Plattner rule in their reductive ring-opening with LTBH.The β-glycosidic 2,3-ditosylate 15 reacts less readily, and gives 20-23, with 20 preponderating.The 2-O-methyl-3-O-tosyl-β-D-glucopyranoside 24 is partly desulfonylated and partly desulfonyloxylated, whereas its 3-O-methyl-2-O-tosyl isomer 27 undergoes desulfonylation exclusively.The reductions of 1, 2, and 8 by LTBH are compared with those previously effected by lithium aluminum hydride, which are slower, involve considerable desulfonylation, and afford lower yields of deoxyglycosides, with the main products differing from those obtained by the action of LTBH.Mechanistic differences associated with the two reductants are discussed.
