Syntheses of Branched Non-1-ynitols by Chemoselective Addition of (Trimethylsilyl)-propargylmagnesium Bromide at the Anomeric Center of Side Chain Halogeno Functionalized Carbohydrates

摘要

A convenient method for the syntheses of non-1-ynitols 8a-8d, by chemoselective addition of (trimethylsilyl)-propargylmagnesium bromide at the anomeric center of a 1-unprotected sugar, in the presence of 3-C-halide and 3-C-silyl functions in the side chain is described. In addition, an efficient method for the synthesis of 3-C-hydroxy-methyl sugar 3 via the addition of C_1 silyl Grignard reagents to ulose 1 and subsequent oxidation by the Fleming-Tamao method in excellent yields is reported. Also, a suitable acid-catalyzed isomerization of the 1,2-O-isopropylidene group to the 2,3-O-isopropyli-dene group (5a-5f), to get access to the anomeric center, in good to excellent yields has been depicted.