Synthesis of 2-(β-d-glycopyranosyl)nitroethenes and -nitroethanes via aldehydo derivatives

pH-Controlled ozonolysis of the sodium nitronate forms of β-d-hexopyranosylnitromethanes (2,6-anhydro-1-deoxy-1-nitroheptitols) at room temperature produced the corresponding 2,6-anhydroheptoses. Without isolation, these glycosylated formaldehydes were converted by the conventional nitromethane route to the corresponding 2-(β-d-hexopyranosyl)nitroethenes (8a–c), via the intermediate acetylated 2-(β-d-hexopyranosyl)-2-hydroxynitroethanes. A spontaneous β-elimination of the acetoxy group vicinal to the nitro group occurred in acidic medium with the 2-acetamido-2-deoxy-β-d-glucopyranosyl derivative, but did not occur with the parent β-d-glucopyranosyl compound or its d-galacto or d-manno epimers. 2-C-Glycosylated nitroethenes were further transformed by a regioselective catalytic reduction to 2-(β-d-hexopyranosyl)nitroethanes.