Synthesis and Utility of 2-(Benzoyloxyimino)-2-deoxy-α-D-lyxo- hexopyranosyl Bromide as a Novel α-D-Talosaminide Building Block.

A novel alpha-D-talosaminyl donor, 2-(benzoyloxyimino)-2-deoxy-alpha-D-lyxo-hexopyranosyl bromide has been synthesized in a total yield of 32% over 6 steps from D-galactose. The utility of the donor was evaluated for the elaboration of alpha-D-TalNAc-(1-->6)-alpha-D-Gal, alpha-D-TalNAc-(1-->6)-alpha-D-Glc, and alpha-D-TalNAc-(1-->3)-L-serine derivatives by a simple 3-step sequence, comprising alpha-selective glycosylation of appropriately protected acceptors of D-galactose, D-glucose, and L-serine, talo-selective hydroboration of the oxyimino function to an amino group, and N-acetylation.