Figure 5.
Hydroxy acid side chain size dictates native α-depsipeptide selectivity. Unbuffered 7 day, 65 °C drying of xD and xE building blocks showing 2-mers and percent α-linkage by integration. The α and γ regioisomers of (gE)2 appear to overlap; thus, their relative abundances are indeterminate. Hydroxy acid side chains are shown in each panel. The identities of the α- and γ-linked 2-mers of fE were determined using synthetic standards (Figure S26), while the 2-mers of fD were identified using an α-linked standard and by analysis of the degradation profile of the 2-mers (Figures S26–S27). fD and fE samples underwent drying with 1 equiv of 2-hydroxypyridine to prevent precipitation (Figure S28).