SYNTHESIS OF TETRAACETAL PENTAOXA-CAGES AND CONVEX OXA-CAGES BY OZONOLYSIS OF 7-OXABICYCLO[2.2.1]HEPTENES

Tetraacetal pentaoxa-cage compounds 4a and 4b and convex oxa-cage comp ounds 6, 7 and 8 are synthesized from alkylfurans in three steps. Ozon olysis of the endo adducts 2a and 2b in dichloromethane at - 78 degree s C followed by reduction with dimethyl sulfide gave the tetraacetal p entaoxa-cages 4a and 4b in 85-90% yields, respectively. Ozonolysis of 2a and 2b in dichloromethane at - 78 degrees C followed by treatment w ith triethylamine gave the convex era-cages 6, 7 and 8 in 85-90% yield s, respectively. The synthesis of the tetraacetal pentaoxa-cage 12, po ssessing aromatic substituents directly on the skeleton of the era-cag es, has also been accomplished.