Synthesis of thiodisaccharides using phase-transfer catalysis
Synthesis of thiodisaccharides or thioglycosides was performed by phase-transfer catalysis using phosphonium or ammonium salts. Starting from glycosyl halides, reaction with Na2S gave the corresponding thiodisaccharides with inversion of configuration at the anomeric centre. With unstable glycosyl halides, a solid-liquid system was used. Unsymmetrical thiodisaccharides and 1-thioglycosides were prepared by reaction of glycosyl halides with thiolate or 1-thioglucose under p.t.c. conditions.