Isotopic Labelling of Quercetin 4′-O-β-d-Glucoside

[2-13C]-Quercetin-4′-O-β-glucoside was synthesised in four steps and 28% yield from barium [13C]-carbonate. This short route will be applicable to the synthesis of radiolabelled quercetin-4′-O-β-d-glucoside from barium [14C]-carbonate. The most important feature is control of the regiochemistry and stereochemistry of glycosylation before introduction of the isotopic label. The synthesis also uses only benzyl protecting groups allowing global deprotection in the last step.