OZONOLYSIS OF 2-ENDO-7-ANTI-DIACYLNORBORNENES - A NEW ENTRY FOR THE SYNTHESIS OF PENTACYCLO[5.5.1.0(3,11).0(5,9).0(8,12)]TRIDECANES

A new route for the synthesis of the title compounds 4a, 4b, 10a, and 10b has been developed via ozonolysis of 2-endo-7-anti-diacylnorbornen es 3a, 3b, 9a, and 9b. The synthesis of the unsubstituted (parent) com pound 4a of tetraacetal tetraoxa-cages has been accomplished for the f irst time by this new entry. Ozonolysis reactions of 3a, 3b, and 9a we re also performed in CDCl3 for understanding the final ozonide structu res and the ozonation chemistry. Ozonolysis of 3a, 3b, and 9a in CH2Cl 2 at -78 degrees C followed by treatment with triethylamine provided a n indirect support for the structures of the final ozonides 11a, 11b, and 14. (C) 1997, Elsevier Science Ltd.