Divergent Total Syntheses of (+)‐Vulgarisins A–E

Abstract

AbstractThe asymmetric total syntheses of (+)‐vulgarisins A–E, which share a rare and highly oxygenated [5‐6‐4‐5] tetracyclic core structure that were isolated fromP. vulgarisLinn., have been described for the first time in a divergent manner. Key transformations include: 1) a catalytic asymmetric intramolecular cyclopropanation to forge the A ring bearing desired stereochemistry at C14; 2) a one‐pot borylation/conjugate addition process for creation of the C1−C11 bond; 3) a Wolff ring contraction to assemble the bicyclo[3.2.0]heptane subunit (CD rings); and 4) a stereocontrolled pinacol cyclization for construction of the central B ring of the natural products.