Cycloaddition of glycosylated butadienes in the synthesis of natural quinone analogs

Diels-Alder reactions of naphthoquinones with substituted hydroxybutadienes containing a carbohydrate moiety proceed in a regioselective fashion, yiel ding the corresponding C-glycosylated anthraquinones. A nucleoside having a n anthraquinone fragment was synthesized by removal of isopropylidene prote ction from C-glycosylated anthraquinone, followed by reaction with silylate d 5-methyluracil. An O-formyl erythrose derivative containing an anthraquin one fragment was obtained by acid hydrolysis of C-glycosylated anthraquinon e and subsequent periodate cleavage of the hydrolysis product.