Only N-phosphoryl serine and threonine methyl esters were catalyzed by imidazole, A new type of pentacoordinate phosphorus intermediate was proposed.

The introduction of flexible pendants chains onto the backbone improves the stability and processability allowing a more complete characterization of the materials.

In general, bulky side-chain and hydrogen bonding are in favor of the formation of stable helical conformation for polymers, which endows them with high optical property and some special performance.