The stereoselective synthesis of unnatural R-amino acids1 is currently a subject of enormous interest mainly due to the increasing biological and therapeutic applications of modified peptides. 2 Over the last few years, we have been involved in a project devoted to the enantioselective synthesis of several structural types of N-Boc amino acids and dipeptide isosteres. 3, 4 Our approach, which is based on the intermediacy of ...