Dehydrative Sialylation with C2-Hemiketal Sialyl Donors
摘要:
[GRAHPICS]A new method for sialylation involving the dehydrative coupling of sialyl donors with the reagent combination of (p-nitrophenyl)(phenyl) sulfoxide and triflic anhydride is reported. This process establishes sialyl C2-hemiketals as viable sialyl donors for complex carbohydrate synthesis.
A New C(1)-Auxiliary for Anomeric Stereocontrol in the Synthesis of α-Sialyl Glycosides
摘要:
[GRAPHICS]The installation of the novel N,N-dimethylglycolamide ester auxiliary onto the C(1)-position of protected neuraminic acid donors allows for the exploitation of C(1)-neighboring group participation to generate sialoside conjugates with good to excellent or-selectivity under a variety of sialylation protocols, including those that would otherwise lead to nonselective or beta -selective sialoside products.