(R)-2-Phenylglycine ethyl ester was found to be a cheap and effective auxiliary for the preparation of aliphatic α, α-difluoro-β3-amino esters via a Reformatsky reaction performed under sonication conditions. The products were obtained in good to high yield and≥ 96: 4 dr, thus providing a new stereoselective route to this under-represented class of compounds. A facile one-pot removal of the phenylglycine moiety and concomitant Boc protection ...