New Preorganized γ-Amino Acids as Foldamer Building Blocks

An asymmetric synthesis of two new diastereomeric γ-amino acids is described. Both molecules contain a cyclohexyl ring to limit conformational flexibility about the Cα-Cβ bond; they differ in having cis vs trans stereochemistry on the ring. Residues derived from the cis γ isomer are shown to support helical secondary structures in α/γ-peptide oligomers.