Enantioselective Synthesis of the Sporolide Quinone Acid Fragment
The sporolide quinone acid is a key fragment in the biosynthesis of the complex heptacyclic marine metabolite sporolide. We report a concise enantioselective route to this fragment, which is obtained in seven steps with 65% overall yield from trimethoxybenzene. The enantioselective transfer reduction is achieved by Ipc2BCl, and the absolute configuration of the product secured by X-ray analysis of its cinchonine salt. The target fragment is then obtained by methylation and oxidation to the quinone by AgO.