A Convergent Total Synthesis of (+)-Ineleganolide

ABSTRACT: We report the total synthesis of the furanobutenolide-derived diterpenoid (+)-ineleganolide. The synthetic approach relies on a convergent strategy, based on the coupling of two enantioenriched fragments which are derived from (-)-linalool and (+)-norcarvone respectively. A high-yielding, one-step Michael addition and aldol cascade furnishes a pentacyclic framework as a single diastereomer, overcoming previous challenges in controlling stereochemistry. The endgame features an O2 facilitated C-H oxidation and a samarium diiodide induced semi-pinacol rearrangement to furnish the highly rigid central seven membered ring.