We calculated the values of r, d, φ1, and φ2 of 2-oxabicyclo[2.2.2]octanes from the X-ray data of compounds 30, 57. The related parameters for bicyclo[2.2.2]octanes 58, 31 59, and 60 were calculated from their X-ray data published in the literature. The corresponding parameters for the parasubstituted phenyl ring were calculated from the reported crystal structure of the anticancer drug Imatinib (Figure ). Analysis of this data revealed that the geometric properties of 2-oxabicyclo[2.2.2]octanes were indeed very similar to those of the para-substituted phenyl ring. The distance r in 2-oxabicyclo[2.2.2]octanes was ca. 0.3 Å shorter than that in the para-phenyl ring: 2.54-2.56 Å vs 2.88-2.89 Å (para-phenyl). The distance d between substituents in 2-oxabicyclo[2.2.2]octanes was also ca. 0.3 Å shorter than that in the para-phenyl ring: 5.56-5.58 Å vs 5.90-5.93 Å (para-phenyl). The difference in collinearity of vectors was insignificant, as angles φ1 and φ2 were almost identical in both scaffolds: 176-177° vs 178-179° (para-phenyl). Interestingly, even in the para-substituted phenyl ring (Imatinib) in the crystal phase the observed angles φ1 and φ2 deviated from the ideal value of 180°. It must be noted, that all parameters, -r, d, φ1 and φ2, -were also almost identical in both bicyclo[2.2.2]octanes (58-60) and 2-oxabicyclo[2.2.2]octanes (30, 57) (Figure ).