Total Synthesis and Determination of the Absolute Configuration of Parimycin.

The first total syntheses of (±)-parimycin and (R)-parimycin were accomplished from O-methylnaphthazarin (6) in nine synthetic steps. Intermolecular Diels-Alder reaction of 6 with diene 7, cyclodehydrogenation catalyzed by iodine-dimethyl sulfoxide, and sodium dithionite reduction were the key steps. The absolute configuration of natural parimycin was determined to be S.