“Carba” peptide bond surrogates Different approaches to Gly‐Ψ(CH2‐CH2)‐d,l‐Xaa pseudo‐dipeptide units

Abstract
Racemic “carba” pseudo-dipeptide units such as Gly-Ψ(CH2-CH2)-d,l-Xaa were obtained either through the Horner-Emmons condensation of N-tert.-butyloxycarbonyl-βalaninal with the appropriate substituted triethyl phosphonoacetate, or from commercially available 3-carbethoxy-2-piperidone.