Total synthesis of aphadilactones A-D.

The first total synthesis of aphadilactones A-D, diastereomeric natural products recently isolated from the Meliaceae plant Aphanamixis grandifolia by Yue and co-workers, which possess an unprecedented carbon skeleton, has been achieved. The synthesis features a catalytic asymmetric hetero-Diels-Alder reaction to form the dihydropyran ring, concurrent installation of the lactone and furan moieties via a tandem acid-catalyzed acetal cleavage, oxidation, and cyclization process, and an intermolecular Diels-Alder reaction to forge the target products.