CYCLOADDITIONS BETWEEN CARBONYL OXIDES AND DICARBONYL-COMPOUNDS - ISOLATION AND CHARACTERIZATION OF NOVEL POLYCYCLIC 1,2,4,6-TETROXEPANE DERIVATIVES

Formaldehyde O-oxide reacts with dicarbonyl compounds to produce mono- ozonides formed by conventional [3 + 2] cycloadditions to an aldehydic carbonyl group of the substrate, and/or polycyclic 1,2,4,6-tetroxepan e derivatives arising from formal [3 + 2 + 2] cycloadditions involving both carbonyl groups. Similar reactions between the more highly subst ituted carbonyl oxides, benzaldehyde and octanal O-oxides, and dicarbo nyl compounds yielded the corresponding mono-ozonides as the sole isol able cycloaddition products. In certain favourable cases, mono-ozonide s could undergo acid-catalysed intramolecular rearrangement to the cor responding 1,2,4,6-tetroxepanes. X-Ray crystallographic analyses of tw o 1,2,4,6-tetroxepanes, 6a and 13b, are recorded.