Total Synthesis of Acortatarin A Using a Pd(II)-Catalyzed Spiroketalization Strategy

The total synthesis of acortatarin A relying on a Pd(II)-catalyzed spiroketalization is reported. This strategy allows a single stereocenter in the spiroketalization substrate to produce the target efficiently under mild conditions, installing the necessary oxygenation in the backbone through an allylic transposition. The synthesis also verifies that pollenopyrroside B and acortatarin A are the same compound, and electrochemical studies suggest that the reported bioactivity is not due to simple antioxidant properties.