Synthesis and X-ray analysis of 2,3,5,6,11-pentaoxabicyclo[5.3.1]undecanes

Abstract

The reactions of bicyclic ozonides and aldehyde- or ketone-derived peroxides, preformed or generated in situ, in the presence of chlorosulphonic acid afford the corresponding 2,3,5,6,11-pentaoxabicyclo[5.3.1]undecanes. In addition, 1,2,4,5-tetraoxans are often isolated from the product mixture. Mechanisms are proposed to account for the observed peroxidic products. An X-ray analysis of the crystalline product (4b) confirms the general structure and reveals that it is solely the exo-isomer.