Synthesis of (R) and (S) enantiomers of Fmoc-protected 1,2,4-oxadiazole-containing β3-amino acids from Fmoc-(R)-β-HAsp(OtBu)-OH

Fmoc-(R)-β-HomoAsp(OtBu)-OH was used for the synthesis of both (R) and (S) enantiomers of various Fmoc-protected 3-substituted 1,2,4-oxadiazole-containing β3-amino acids. The 1,2,4-oxadiazole heterocycle was formed using sodium acetate, a Fmoc-compatible and efficient catalyst for cyclodehydration.