Synthesis of Dioxa-Cages as a New Probe for the Stereochemistry of the Bisadducts of p-Quinone with Cyclopentadiene and Cyclohexadiene

The synthesis of dioxa-cages via iodine-induced cyclization reaction can be used as a new method for the determination of the stereochemistry of the bisadducts of p-quinone with cyclopentadiene and cyclohexadiene. The bisadducts 2 and 8 were converted into the dioxa-cages 13a and 13b via a three-step sequence, respectively. The stereochemistry of 13a and 13b was determined on the basis of NOE experiments.