ABSTRACT
Reagents and conditions: (a) HCl (generated in situ by reaction of AcCl with MeOH), AcCl, CH2Cl2, +4°C; (b) Na2HPO4, MeCN, re—ux.
O-Acetylated N-acetylneuraminic acid (Neu5Ac) glycal (3) is the key intermediate for preparation of the corresponding glycosyl donors with an auxiliary stereocontrolling group at the C-3, which have been glycosyl donors of choice for the synthesis of complex sialooligosaccharides.1 Compound 3 has also found application in synthesis of an anti-in—uenza drug (Zanamivir), which has recently been commercialized.2 Although several methods for the preparation of this important intermediate
Experimental Methods ...........................................................................................246 General Methods ...............................................................................................246
