The first total synthesis of calabricoside A

Quercetin 3-O-[α-l-rhamnopyranosyl-(1→2)-α-l-arabinopyranoside]-7-O-β-d-glucopyranoside (calabricoside A), a new flavonol triglycoside isolated from the aerial parts of Putoria calabrica showing strong radical scavenging activity, was synthesized through a combination of phase-transfer-catalyzed C-3 glycosylation and AgOTf promoted homogeneous C-7 glycosylation in CH2Cl2.