Stereoselective Palladium-Catalyzed Allylic Alkylation of Peptide Enolates

Significance

The authors report the palladium-catalyzed allylic alkylation of chelated peptide ester enolates. Interestingly, the diastereoselectivity is independent of the allylic substrate used, regardless of the degree of substitution or functionalization. Instead, the stereochemistry of the reaction is controlled by the substitution of the peptide chain. Hence, the steric bulk of the amino acid side chain highly influences the diastereoselectivities obtained. Also, it was found that TFA gave superior diastereomeric ratios compared to Boc- and Z-protecting groups.