Synthesis of novel (R)- and (S)-piperidazine-3-phosphonic acids and transformation into (R)- and (S)-pyrrolidine-2-phosphonic acids

The first synthesis of a pair of (R)- and (S)-piperidazine-3-phosphonic acids was performed via a one-pot process of hetero Diels–Alder reaction and Lewis acid-catalyzed phosphonylation. The absolute configuration of the target compounds was established by a novel transformation into known (R)- and (S)-pyrrolidine-2-phosphonic acids.