Total Synthesis-Assisted Structure Determination and Biological Evaluation of Cytotoxic Cyclodepsipeptide Destruxin F

The structure determination of destruxin F was achieved by total synthesis. Four isomers of the α,γ-dihydroxycarboxylic acid derivatives were comprehensively prepared from chiral glycidols in an asymmetric manner, enabling the successful synthesis of all structural candidates of destruxin F. The spectral data of the (1αR,1γR)-isomer were in good agreement with those of natural destruxin F, leading to the determination of the absolute configuration of the undetermined chiral centers as 1αR and 1γR, respectively. Furthermore, biological evaluation of the synthetic compounds revealed that the proper conformation of the cyclic peptide scaffold is required to exhibit the cytotoxicity and that the structure of α-hydroxycarboxylic acid moiety regulates the potency of biological activity.