Synthesis of Benzannelated Pyranosides

Article abstract of DOI:10.1021/jo00132a037

Ethyl and benzyl 2,3-dideoxy-α-D-glycero-hex-2-enopyranosid-4-uloses (e.g., 9-11) were prepared from D-glucal.The enones reacted with 1-methoxy-1,3-butadiene or 1-<(trimethylsilyl)oxy>-1,3-butadiene to afford the corresponding <4 + 2> cycloadducts.DDQ aromatization and subsequent elaboration of the cycloadducts gave benzannelated pyranosides.Amino sugar derivatives also were prepared.Aromatization of the (trimethylsilyl)oxy adducts directly afforded the corresponding phenols, but the reaction was found to be of limited scope.The stereochemistry of intermediates and products and subtleties of the DDQ reaction are discussed.