Synthesis and revised stereochemical assignment of C-allyl glucopyranosides and derivatives.

α- and β-C-allylglucopyranosides and hydroxy-, bromo- and azido-derivatives were prepared through allylation at C-1 of methyl 2,3,4,6-tetra-O-benzyl-D-glucopyranoside or 1-O-acetyl-2,3,4,6-tetra-O-benzyl-D-glucopyranose and subsequent chemical modifications of the alkene on the anomeric arm. However, we picked out some discordance between some recent published studies and our results. After a thorough work of characterization and NMR analysis, we unambiguously confirmed α and β stereochemistry of the two series of compounds and fully described for the first time β-C-propyl alcohol, bromide and azide of 2,3,4,6-tetra-O-benzyl-D-glucopyranose.