Oxidation of the readily available diketone 2 affords high yields of the symmetrical dilactone 5, from which the all-endo-tetrakis (hydroxymethyl) norbornane 10 can be made. A related tetrol 22 is also described. These tetrols are dehydrated to polycyclic di-ethers 12, 13, and 23 which constrain their oxygen atoms in rigid proximity within their structures.