Synthesis of N-unsubstituted, mono- and disubstituted carbohydrate-1-O-carbamates and their behaviour in glycoside syntheses Original Research Article

The syntheses of 44 1-carbamates from six different 1-O-unprotected carbohydrate derivatives (compounds 1–6), representing typical protecting pattern in glycoside synthesis, are described. The carbamate function is N-unsubstituted (compounds 1b–6b), mono- (compounds a: N-trichloroacetyl, c: N-monochloroacetyl, d: N-acetyl, e: N-ethyl, f: N-allyl, g: N-phenyl) or disubstituted (compounds h: imidazolyl, i: N-diethyl, j: N-diphenyl). Additionally, three N-chlorosulfonyl carbamates are synthesized and used as intermediates for the synthesis of N-unsubstituted compounds b. The accessibility of these compounds is described and compared. Some of the carbamates (1, 4, 5a–j) are used as model compounds for systematic investigations in glycoside syntheses. Selected experimental data (reaction conditions, anomeric ratios, rotation values, selected NMR data) are tabulated.