Synthesis of novel triacetal trioxa-cage compounds by ozonolysis of bicyclo[2.2.1]heptenes and bicyclo[2.2.2]octenes

Several novel triacetal trioxa-cage compounds 11a-11g, 13, 15, 17 and 19 are synthesized in a short sequence. Ozonolysis of bicyclo[2.2.1]heptenes 4a-4c, 8a-8c, 10a, 10b and 14 in dichloromethane at -78 degrees C followed by reduction with dimethyl sulfide gave triacetal era-cages 11a-11g, 13 and 15 in moderate yields, respectively. Ozonolysis of bicycle[2.2.2] octenes 16 and 18 under the same reaction conditions gave triacetal era-cages 17 and 19 in moderate yields, respectively.