Fluorocyclopropane-Containing Proline Analogue: Synthesis and Conformation of an Item in the Peptide Chemistʼs Toolbox

[Image: see text] Over the years, numerous modifications to the structure of proline have been made in order to tune its effects on bioactive compounds. Notably, the introduction of a cyclopropane ring or a fluorine atom has produced interesting results. Herein, we describe the synthesis of a proline containing fluorocyclopropane. This modified amino acid was inserted into a tripeptide, whose conformation was studied by nuclear magnetic resonance and density functional theory calculations.