O-Glycopyranosyl-N-hydroxysuccinimides, e.g. I (R = Ac, Bz), have been synthesized by treatment of peracetylated glucose or lactose with N-hydroxysuccinimide. With boron trifluoride etherate in CH2Cl2, peracetylated sugars gave predominantly the b-anomer. Trimethylsilyl trifluoromethanesulfonate in nitromethane, however, gave predominantly the a-anomer. Treatment of I (R = Ac) with various nucleophiles (methoxide, hydroxide, and pentylamine) gave the corresponding deacetylated N-(succinyl)glucopyranosylhydroxylamines II [R1 = OH, OMe, NH(CH2)4Me], in almost quant. yield. These derivs. are suitable for the formation of glycoconjugates or attachment of carbohydrates to solid phases using the opened succinimide as linking arm. [on SciFinder (R)]