Synthesis of l-xylose derived cyclohexenephosphonates—versatile precursors of sialidase inhibitor libraries

l-xylo Configured cyclohexenephosphonates 1 and 2 have been synthesized as scaffolds for sialidase inhibitor libraries. These compounds were obtained by chain elongation and cyclization of suitably protected l-xylose. An unexpected phosphorylation was observed, however, the resulting phosphate could be removed in a final enzymatic step. Optimization of the reaction conditions avoided the undesired phosphorylation and opened the way to a purely chemical synthesis.