Chemistry of 1-methylenesugars: synthetic utilizations to 1'-C-methyl-saccharides and related carbohydrates

- The efficient synthesis of protected 1-methylenesugars and their acid-catalyzed O-glycosidation are mentioned in connection with that of 1-C-methyl-pyranoses. Application of this process to synthesis of the pentasaccharide PI-88 analogue was accomplished in a protected form. Also the syntheses of trehalose analogues and ulsonic acid derivatives were successful in the similar process. 1,3-Dipolar cycloaddition with nitrones provides the new types of spiro-heterocycles combined with carbohydrates. The closely related methylene-carbohydrates also provide a novel synthetic process for cyclitols that are useful synthetic intermediates for voglibose and related drugs.