Twenty-seven mono-tetrasaccharidic 2-(trimethylsilyl) ethyl (TMSET) glycosides were synthesized by the Konigs-Knorr-type method in combination with a wide range of standard reagents for glycoside synthesis and protecting-group chemistry. Variously protected TMSET glycosides were treated with BF,. EkO (0.7-0.8 equiv) and different carboxylic anhydrides (1.1-15 equiv) in toluene at 22-55" C, which gave in one step the corresponding protected ...