Summavy. The synthesis of the following compounds and reaction products thereof are described : endo, endo-2,5-dihydroxy-9-oxabicyclo[4.2. llnonanc (3-5), epimeric 2,6-dihydroxy-9oxabicyclo[3.3. llnonanes (endo, endo : 6-8, exo, exo : 29-32, and endo, exo : 43-45), and endo, exo-2,7-dihydroxy-9-oxabicyclo[3.3. llnonane (46-50).