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

摘要

Abstract The asymmetric total syntheses of (+)‐vulgarisins A–E, which share a rare and highly oxygenated 5‐6‐4‐5 tetracyclic core structure that were isolated from P. vulgaris Linn., 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 bicyclo3.2.0heptane subunit (CD rings); and 4) a stereocontrolled pinacol cyclization for construction of the central B ring of the natural products.