A general procedure for the synthesis of 1-O-acyl-b-D-glucuronic acids, e.g. I, using the benzyl 1-O-trichloroacetimidoyl-2,3,4-tri-O-benzyl-D-glucopyranuronate as donor is exemplified by the synthesis of the urine metabolites of (S)-naproxen, desmethyl (S)-naproxen, indoprofen, and carboxymefloquine. The key intermediate benzyl 2,3,4-tri-O-benzyl-D-glucopyranuronate is easily accessible in four steps (29%) from the peracetylated b-D-glucuronic acid. [on SciFinder (R)]