obtained starting from a dehydrotetramer of 2,4-dimethylphenol. The final installation of the phenol component requires a domino sequence based on electrophilic substitution and a ketalization process. The molecular structure of these dioxa[4.3.3]propellanes was elucidated by 2D NMR techniques as well as X-ray analysis of suitable single crystals. Most of these polycyclicproducts were formed with high