Synthetic Studies toward Actinorhodin and γ-Actinorhodin by using a Homo-coupling Strategy: Synthesis of Hemiactinorhodin and Hemi-γ-actinorhodin

A homo-coupling strategy toward the synthesis of actinorhodin and gamma-actinorhodin has been explored. The monomeric unit was synthesized by employing an efficient combination of Dotz benzannulation and oxa-Pictet-Spengler reactions. Attempts towards oxidative homo-coupling of the pyranonaphthalene monomer intermediate to give dimer were unsuccessful. Later, monomer pyranonaphthalene was carried forward to complete the synthesis of hemiactinorhodin and hemi-gamma-actinorhodin.