Streamlined synthesis of per-O-acetylated sugars, glycosyl iodides, or thioglycosides from unprotected reducing sugars.
Solvent-free per-O-acetylation of sugars with stoichiometric acetic anhydride and catalytic iodine proceeds in high yield (90-99%) to give exclusively pyranose products as anomeric mixtures. Without workup, subsequent anomeric substitution employing iodine in the presence of hexamethyldisilane (i.e., TMS-I generated in situ) gives the corresponding glycosyl iodides in 75-95% isolated yield. Alternatively, and without workup, further treatment with dimethyl disulfide or thiol (ethanethiol or thiocresol) gives anomerically pure thioglycosides in more than 75% overall yield.
Mukhopadhyay
Balaram
B
Centre for Carbohydrate Chemistry, School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich NR4 7TJ, UK.
Kartha
K P Ravindranathan
KP
Russell
David A
DA
Field
Robert A
RA
D000107:Acetylation; D002241:Carbohydrates / Q000138:chemical synthesis*; D002384:Catalysis; D006027:Glycosides / Q000138:chemical synthesis*; D007455:Iodine / Q000737:chemistry*; D015394:Molecular Structure; D013865:Thioglycosides / Q000138:chemical synthesis*
D002241:Carbohydrates; D006027:Glycosides; D013865:Thioglycosides; D007455:Iodine