Formal total synthesis of shikonin via Dِtz benzannulation

The Dِtz benzannulation reaction provides mild conditions for the construction of highly functionalized aromatic compounds. We have utilized this method for the formal total synthesis of shikonin. The key step in our approach is the application of the Dِtz benzannulation reaction between Fischer a chromium carbene complex and an optically active alkyne for the construction of the aromatic skeleton. This is followed by protecting group manipulation and formation of the epoxide moiety using the Sharpless procedure.