Synthetic studies toward sordarin: building blocks for the terpenoid core and for analogues thereof

The different ways to bi- and tricyclic building blocks for the elaboration of sordaricin and its analogues are discussed. The target molecules are obtained through inter- and intramolecular Diels-Alder reactions of cyclopentadienes and the unusual properties of 3-cyanoenones and 1-cyanocyclopetadienes are circumvented.