Highly regio- and stereo-selective Diels–Alder reactions of 5-(2′,3′,4′,6′-tetra-O-acetyl-β- D -glucopyranosyloxy)-1,4-naphthoquinone

The title compound 1b reacts with cyclopentadiene to give a single cycloadduct, assigned the stereostructure 6a by X-ray crystallography; single cycloadducts, i.e.4c and d, also arise in the corresponding reactions involving the dienes 2b and c.