IMPROVED PRACTICAL METHOD FOR SYNTHESIS OF ARYL C-GLYCOSIDES FROM UNPROTECTED METHYL GLYCOSIDES AND 1-HYDROXY SUGARS

Aryl C-glycosidations of the unprotected methyl glycosides 9-12 and th e unprotected 1-hydroxy sugars 14 and 15 with 2-naphthol 6 using TMSOT f proceed much more effectively than those of the acylated methyl glyc osides 4 and 5; the unprotected methyl glycoside 10 is also smoothly c oupled with other phenol and naphthol derivatives 25-27 to give the co rresponding unprotected o-hydroxyaryl beta-C-glycosides in high yields (TMSOTf = trimethylsilyloxytrifluoromethanesulfonate).