Highly Convergent Total Synthesis of (+)-Lithospermic Acid via a Late-Stage Intermolecular C−H Olefination

Abstract

The total synthesis of (+)-lithospermic acid is reported, which exploits two successive C−H activation reactions as key steps. Rh-catalyzed carbene C−H insertion reaction utilizing Davies’s catalyst was used to forge dihydrobenzofuran core, and a late-stage intermolecular C−H olefination coupled the olefin unit with the dihydrobenzofuran core to construct the molecule in a highly convergent manner.