Concise total syntheses of phelligridins A, C, and D.

We have established a concise and scalable synthetic pathway for phelligridins A (1), C (2) and D (3). The synthetic highlights were Suzuki-Miyaura coupling and aldol-type condensation of α-pyrone. Phelligridin A was synthesized in four steps, while phelligridins C and D were each synthesized in six steps. Furthermore, we have revealed that the whole structure is essential for the cytotoxicity of phelligridins.