Abstract The Schöllkopf bislactim ether asymmetric amino acid synthesis was coupled with a subsequent enzyme mediated ester hydrolysis to generate a practical synthesis of both D and L enantiomers of Fmoc-Abu [PO (OCH 2 CH CH 2) 2]-OH (6). With this building block phosphonopeptide isosteres of serine phosphopeptides are accessible by Fmoc-solid phase peptide synthesis.