Straightforward asymmetric synthesis of Ala-Ψ[CF=CH]-Pro, a proline-containing pseudodipeptide bearing a fluoroolefin as a peptide bond mimic

From ethyl-2-oxocyclopentanecarboxylate, we developed an asymmetric synthesis of the fluorinated dipeptide Ala-Psi[(Z)CF=CH]-Pro analogue of the transoid parent dipeptide. The fluorinated pseudodipeptide could be incorporated into various peptides or proteins for conformational, structural studies and biological activity studies and could also play a relevant role as an enzyme inhibitor.