AN EFFICIENT METHOD FOR THE STEREOSELECTIVE SYNTHESIS OF 2-AMINO-BETA-D- AND ALPHA-D-GLYCOSIDES FROM PERACYLATED SUGARS USING ACTIVE ACIDICSPECIES

In the presence of a catalytic amount of tin(II) trifluoromethanesulfo nate or ytterbium(III) trifluoromethanesulfonate, various 2-amino-beta -D-glucopyranosides or galactopyranosides are stereoselectively synthe sized in high yields from oethoxycarbonylamino)-2-deoxy-beta-d-glucopy ranose and galactopyranose or allyloxycarbonylamino-2-deoxy-beta-d-glu copyranose on treatment with alkyl trimethylsilyl ethers or free alcoh ols. Further, 2-amino-alpha-D-glucopyranosides or galactopyranosides a re respectively prepared in high yields with almost perfect stereosele ctions from the same glycosyl donors through an anomerization step by using a catalyst generated from tin(IV) chloride and a silver salt.