Ir-Catalyzed, Stereoselective Total Synthesis of (+)-Rubriflordilactone A

A stereocontrolled asymmetric total synthesis of the <i>Schisandra</i> nortriterpenoid (+)-rubriflordilactone A employing Krische's Ir-catalyzed 2-(alkoxycarbonyl)allylation for late-stage γ-butenolide formation is described. Additional noteworthy aspects include the integration of Carreira's Ir/amine dual-catalyzed allylation, Suzuki coupling, and Catellani reaction, resulting in the formation of an indane iodide. The alkylation of lactone <b>7</b>, followed by RCM, A-ring formation via condensation of the B-ring lactone with Bestmann ylide, and Morken's Pt-catalyzed diboration/oxidation, facilitates the stereoselective formation of the ABCDEF ring system.