Synthesis and applications of β-aminocarboxylic acids containing a cyclopropane ring

To date, a number of synthetic strategies toward cyclopropyl-substituted β-alanines, resulting in structurally defined, highly functionalized amino acids have been introduced. Many of these compounds have been used as reactive building blocks, utilizing the ring strain of the cyclopropane moiety as well as the amino and carboxyl groups for the synthesis of complex heterocyclic systems. Only recently have the title compounds been recognized, since the rigidity introduced by the cyclopropane ring not only constrains a peptide backbone, but also allows the controlled placement of functional groups, mimicking α-amino acid side chains.