Construction of the Hexacyclic Core of Dispirocochlearoids A—C via a Diels−Alder Reaction

Comprehensive Summary The natural products of dispirocochlearoids are complex Ganoderma meroterpenoids featuring a 6/6/5/6/6/6 ring system and are selective COX‐2 inhibitors. Herein, we describe our progress regarding the total synthesis of dispirocochlearoids A—C, in which a hexacyclic skeleton was constructed firstly. The key steps of this work involve an intermolecular [4 + 2] cycloaddition reaction, a ring cleavage approach via TiCl 4 , and the installation of a profoundly sterically hindering lactone.