Total Synthesis, Revised Structure, and Biological Evaluation of Elgonene B and Analogues

Herein, we report the first total synthesis of elgonene B and its congeners, thus resulting in a revision of the configuration at the C-6 carbon of the originally proposed structure of elgonene B. This synthetic approach demonstrates the utility of several important reactions such as the chiral oxazaborolidinium ion-catalyzed Diels–Alder reaction, Ando’s Horner–Wadsworth–Emmons olefination, and the intermolecular Nozaki–Hiyama–Kishi reaction as key steps. Additionally, the study explores the cytotoxic and antibacterial activities of elgonene B and its congeners (1–4).