134133-87-2 2,6,7-Trioxabicyclo(2.2.2)octane, 4-(2-cyclohexen-1-yl)-1-(4-ethynylphenyl)- 4-(2-Cyclohexen-1-yl)-1-(4-ethynylphenyl)-2,6,7-trioxabicyclo(2.2.2)octane