The first total synthesis of calabricoside A

Quercetin 3-O-[alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranoside]-7-O-beta-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. (C) 2003 Elsevier Ltd. All rights reserved.