Oxoalkylphosphonic acids reductive amination

As seen in Scheme 1 a route similar to the biological pathway has now been explored by the independent synthesis of each precursors by chemical means. Work presented in this communication describes the production of synthetic 2-aminoethylphosphonic acids by the controlled reductive amination of 2-oxoalkylphosphonate diesters... 

The reductive amination method has been applied to the preparation of 4-aminoalkylphosphonic acids from 4-oxoalkylphosphonates (Scheme 7.65). ... 

One example of reductive amination of acylphosphonates has been reported. Thus, reaction of dimethyl 1-oxoalkylphosphonates with benzhydrylamine results in the formation of an imine reduced in situ with NalllKOAc),. The reaction is independent of the solvent, and THF, CIFCh and CHCI3 give similar results - After selective removal of the benzhydrylic group by catalytic hydrogenation and hydrolysis with concentrated HCl, the 1 -aminoalkylphosphonic acids are isolated in satisfactory yields (30-60%, Scheme 7.66) ... 

Ryglowski, A., and Kafarski, P., Preparation of 1-aminoalkylphosphonic acids and 2-aminoalkylphosphonic acids by reductive amination of oxoalkylphosphonates. Tetrahedron, 52, 10685, 1996. 

---