Biomimetic Total Synthesis of Bimagnolignan: A Natural Anti-Breast Cancer Agent.

A short scalable biomimetic route to bioactive natural product bimagnolignan ( 1 ) was accomplished. Compound 1 was successfully prepared through a three-step metal-free synthesis from honokiol ( 2 ). Alternatively, 1 was also synthesized by biomimetic transformations that mimic tyrosinase in four steps. The key reactions feature a regioselective acetylation, a highly efficient C(sp 2 )-H oxidation, a cascade aerobic oxidative cyclization/coupling, and a Cu-catalyzed direct oxidative coupling. In addition, cell-based assays validate that 1 is a promising natural lead for HER2-positive breast cancer treatment.