After prosperous dominoreactions towards benzopyrans, the products were used as the starting material in Lewis acid catalyzed and organocatalytic Diels-Alder reactions to build up a tricyclic system. Herein, an asymmetric induction up to 96% enantiomeric excess was obtained by the use of imidazolidinone catalysts. This approach can be utilized to construct the tricyclic system in numerous natural
towards the tricyclic cannabinoid system are presented. The procedures are exemplified by the synthesis of a penta-cycle and various tricycles respectively, in up to 95% enantiomeric excess and provide a versatile entry to this group of natural products with tetrahydrocannabinol (THC) being the most prominent one. Most published strategies are based on the formation of the tricyclicsystem by condensation