Oxa bowls: Synthesis of new tetraoxa-cages and their C-H center dot centerdot center dot O-mediated solid-state architecture

We have envisioned a new family of era-bowls, and a general approach to the se entities has been proposed through polycyclic frameworks having two conv erging olefinic double bonds. Ozonolysis of such molecules was envisaged to give all-cis-tetraaldehyde functionality, which could undergo intramolecul ar cascade acetalization to oxa-bowls having C-2v symmetry. Homohypostrophe ne 16a and its functionalized derivative 16b and hypostrophene 17 on ozonol ysis furnished the oxa-cages 22a, 22b, and 23, respectively. Single-crystal X-ray analysis of 22a and 23 showed an interesting network of C-H ... O in teractions mainly involving the nonacidic cycloalkane hydrogen atoms. The m olecule 22a exhibits an interesting tapelike C-H ... O hydrogen bonding mot if in its crystal structure. On the other hand, the molecule 23 revealed an undulated ribbonlike C-H ... O motif. The "chain of rings" pattern of C-H ... O interactions in 23 has been observed for the first, time in the solid -state structure of oxa-bowls.