Ozonides, formation methanol reaction

Diaryl- and tetraaryl-substituted furans such as tetraphenylfuran (384) for example, yield generally cw-diaroylethylenes such as 380, probably via intermediate ozonide formation.257 Secondary reactions seem to depend very much on the nature of the solvents. Thus, cis-dibenzoylstilbene (380) has been observed by direct photooxygenation of 384 in CS2 as well as by methylene blue-sensitized photooxygenation of 384 in methanol.257,258 However, when the latter reaction was carried out in acetone, epoxide 386 and the enolbenzoate 387 were obtained.258... 

Qolutions of stilbene ozonides in methanol slowly decompose at room temperature with the formation of benzoic acid and benzaldehyde. Other ozonides show similar behavior. However, the reaction rates differ from solvent to solvent and depend on the constitution and configuration of the ozonide. Therefore, we decided to investigate these reactions more carefully. Many new ozonides—especially those with one or more aromatic substituents—had to be prepared, and their configurations had to be established. 

The products depend on the reaction conditions. In the presence of reactive solvent, such as methanol, Path a dominates. Ozonization in an inert medium leads to ozonide (Path b) and peroxide formation (Path c) the relative yield of ozonide and peroxide depends upon the olefin, solvent, and other reaction conditions. 

---