From Amherst (Massachusetts, USA) to Padua (Italy) and back again: Louis A. Carpino's scientifically productive journey

In this work, we studied and discussed a relevant aspect of peptide science, strictly related to the scientific production of Prof. Louis A. Carpino who passed away in early 2019. Specifically, we carried out a statistical survey on the significant 3D-structural parameters (bond lengths, bond angles, and torsion angles) of the currently extensively used 9-fluorenylmethyloxycarbonyl (Fmoc) alpha-amino protecting group introduced by Carpino in peptide synthesis. In this compilation, we considered all 131 X-ray diffraction structures available in the literature on amino acid / linear peptide derivatives and Fmoc-labeled amines. Both Fmoc secondary and tertiary urethane functionalities were examined and separately analyzed.