Synthesis of C -linked α-Gal and α-GalNAc-1'-hydroxyalkanes by way of C2 functionality transfer.

Inspired by reports of water sculpted Tn antigen (α-GalNAc- O -Ser/Thr) epitopes and our interest in producing metabolically more stable C -linked analogs of Tn, we explored the utility of C2 functionality on α-Gal- C -alkenes to deliver hydroxyl to the pendant alkenyl chain. Toward this end, a cyclic carbonate approach gave rise to a single C -linked α-Gal-1'(S)-hydroxyethane in 3 steps, and use of a 2-(hydroxyimino)galactoside cyclization transferred an oxygen to a pendant cis -substituted C -linked alkene affording the R -configuration at the newly formed stereocenter (7:1 dr). Reduction and acetylation of the resultant isoxazoline demonstrated this approach as a viable route to C -linked α-GalNAc-1'-hydroxyalkanes.