CF₂H as a hydrogen bond donor group for the fine tuning of peptide bond geometry with difluoromethylated pseudoprolines

Abstract

CF₂H-Pseudoprolines obtained from difluoroacetaldehyde hemiacetal and serine are stable proline surrogates. The consequence of the incorporation of the CF₂H group is an important decrease of the trans to cis amide bond isomerization energy and a remarkable stabilisation of the cis conformer by an hydrogen bond.