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Iterative One‐Pot α‐Glycosylation Strategy: Application to Oligosaccharide Synthesis
Author(s) -
Liu ChihYueh Ivan,
Mulani Shaheen,
Mong KwokKong Tony
Publication year - 2012
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201200396
Subject(s) - chemistry , trisaccharide , glycosylation , anomer , oligosaccharide , stereochemistry , conjugate , heteronuclear molecule , serine , glycan , nuclear magnetic resonance spectroscopy , organic chemistry , biochemistry , glycoprotein , enzyme , mathematical analysis , mathematics
Abstract Based on the combined use of dimethylformamide (DMF) modulation and neighboring group participation, three iterative one‐pot α‐glycosylation methods, i.e., one‐pot (α,α)‐, one‐pot (β,α)‐, and one‐pot (α,β)‐glycosylations, were developed. These methods are applicable to a range of thioglycosyl donors, confer stereocontrol in α‐/β‐glycosidic bond formation, and thus provide for rapid access to oligosaccharides with various permutations of anomeric configurations. The utility of these one‐pot glycosylation methods is demonstrated in the synthesis of eight non‐natural and natural oligosaccharide targets, including the core 1 serine conjugate, core 8 serine conjugate, the D ‐Gal‐α(1→3)‐ D ‐Glc‐α(1→3)‐ L ‐Rha trisaccharide unit of the cell wall component in Streptococcus pneumoniae , and the D ‐Glc‐α(1→2)‐ D ‐Glc‐α(1→3)‐ D ‐Glc trisaccharide terminus of the N ‐linked glycan precursor. Confirmation of the anomeric configurations of these oligosaccharides is evidenced by 1 H, 13 C, 13 C‐non‐proton decoupling, and heteronuclear correlation 2D NMR experiments. Global deprotection of selected oligosaccharide targets is illustrated.