Total Synthesis of the Antitumor Antibiotic (±)-Fredericamycin A by a Linear Approach

A linear approach to the total synthesis of racemic fredericamycin A (1) through the oxidative intramolecular [4+2] cycloaddition of a (phenylthio)acetylene–cobalt complex is described, which is applicable for the asymmetric total synthesis of naturally occuring 1. The highlight of this work is the aromatic Pummerer‐type reaction with 1‐ethoxyvinyl chloroacetate, which effects the introduction of the oxygen functional group to the internal B‐ring of the highly functionalized, congested polyaromatic ABC‐ring moiety.