One-step synthesis of O-benzyl hydroxamates from unactivated aliphatic and aromatic esters.

We have developed a simple and high yielding one-step method for the synthesis of hydroxamate derivatives directly from a broad range of unactivated esters and the anion of O-benzyl-hydroxylamine generated in situ. The reaction takes place in minutes at -78 degrees C. Very importantly, the method was successfully employed with enolizable esters, including chiral alpha-amino acid esters and peptides, with no trace of racemization/epimerization at the alpha carbon detected.