Efficient synthesis of kaempferol 3,7-O-bisglycosides via successive glycosylation with glycosyl ortho-alkynylbenzoates and trifluoroacetimidates

Selective glycosylation of the 3-OH of 5,4′-di-O-acetyl-kaempferol was achieved with glycosyl ortho-alkynylbenzoates as donors under the catalysis of Ph3PAuNTf2, and subsequent glycosylation of the remaining 7-OH with glycosyl trifluoroacetimidates under the catalysis of BF3·OEt2, after global deprotection, afforded the kaempferol 3,7-O-bisglycosides conveniently.