Formal synthesis of cochlearol A, a meroterpenoid with renoprotective activity

Cochlearol A, a renoprotective meroterpenoid isolated from Ganoderma cochlear, was formally synthesized by intramolecular acetal formation. Its characteristic perhydro-3,9a-epoxybenzo[c]oxepine skeleton was stereoselectively constructed by intramolecular acetal formation employing spiroepoxide as a key intermediate, which was prepared via benzylic oxidation under Nicolaou's conditions employing photochemically activated Pb(OAc)(4) and introduction of epoxide under Concellon's conditions using diiodomethane and methyllithium. (C) 2020 Elsevier Ltd. All rights reserved.