The total syntheses of basiliolide C, epi-basiliolide C, and protecting-group-free total syntheses of transtaganolides C and D.

The total syntheses of basiliolide C and previously unreported epi-basiliolide C are achieved by an Ireland-Claisen/Diels-Alder cascade. The development of a palladium catalyzed cross-coupling of methoxy alkynyl zinc reagents allows for the protecting-group-free syntheses of transtaganolides C and D. Syntheses of transtaganolides C and D are accomplished in a single operation to generate three rings, two all-carbon quaternary centers, and four tertiary stereocenters from a monocyclic, achiral precursor.