Six Natural Phenylethanoid Glycosides: Total Synthesis, Antioxidant And Tyrosinase Inhibitory Activities

Total synthesis of six natural phenylethanoid glycosides (PhEGs) has been accomplished. Key steps in the divergent synthesis strategy involved glycosylation based on trichloroacetimidate donors, and one-pot removal of benzyl and 4,6-O-benzylidene acetal groups by hydrogenation over Pd/C. Among them, four natural PhEGs, scroside D (2), rebouoside B (3), ginkgoside C (4), and ginkgoside D (5) were synthesized for the first time. In the subsequent antioxidant and tyrosinase inhibitory activities evaluation, all compounds showed strong DPPH radical scavenging activities, and compounds1-2,5-6exhibited obvious inhibitory activities against mushroom tyrosinase.