The preparation of 2:1-[α/aza]-oligomer precursors is described via Mitsunobu and exchange of protecting groups protocols in four steps in good yields starting from N-tert-butyloxycarbonylaminophtalimide. Conformational studies showed that these building blocks further led to β-turn-like folded 2:1-[α/aza]-trimer which suggests that they are good candidates to form foldamers.