Nucleophilic addition of 2-(trimethylsilyloxy)furan to a d-glucopyranose oxocarbenium ion

Cp 2 Zr(ClO 4 ) 2 was used as a promoter for nucleophilic addition of 2-(trimethylsilyloxy) furan (TMSOF) to 2,3,4,6-tetra- O -benzyl- d -glucopyranosyl fluoride to give a 2:1:1 mixture of adducts in 80% yield. NMR data and postulated transition states are consistent with a 3:1 ratio of regioisomers at C-5 and C-3 of TMSOF and a 2:1 ratio of threo and erythro α-adducts at C-5.