Stereoselective synthesis of pseudotripeptides incorporating uncommon bis-α-aminoacid derivatives and X-ray analysis. Part 3

Stereoselective synthesis of pseudotripeptides 4, 5, 6, 8, 9, 13 and 14, incorporating an uncommon bis(α-aminoacid) derivative, has been accomplished starting from the L-valine derived chiral synthon 1. The configuration of the introduced stereogenic centres has been assigned on the basis of 1H NMR spectroscopic data. The geometry of the tripeptides, deduced on the basis of 1H NMR parameters and IR spectra, was confirmed by X-ray crystal structure analysis of 6.