Facile Preparation of Protected Furanoid Glycals from Thymidine

The synthesis of O-silyl- and O-acyl-protected furanose glycals from free thymidine was investigated. The method of glycal formation reported by Pedersen et al. was successfully expanded to include 5-ester (toluoyl) protected glycals as well as various combinations of 5‘-ester and 3- and 5-tert-butyldimethylsilyl and tert-butyldiphenylsilyl protection. Gram quantities of furanoid glycals can be prepared in a few days in two−four synthetic steps in overall yields ranging from 17 to 80%.