125101114-Hexaoxadispiro5.2.5.2hexadecanes: Novel Spirofused Bis-Trioxane Peroxides

摘要

A set of new bis-spirofused 1,2,4-trioxanes >4a->d was obtained from the reaction of cyclohexane-1,4-dione with allylic hydroperoxides >2a->d, bearing an additional hydroxy group in the homoallylic position, by diastereoselective photooxygenation of allylic alcohols >1a->d and subsequent BF3-catalyzed peroxyacetalization with the diketone. From the reaction of a monoprotected cyclohexane-1,4-dione >5 with the allylic hydroperoxide >6 derived from the singlet oxygenation of methyl hydroxytiglate, one monospiro compound was obtained, the 1,2,4-trioxane ketone >7, as well as a mixture of the diastereoisomeric syn- and anti bis-1,2,4-trioxanes >8. The structures of bis-1,2,4-trioxanes were examined theoretically by DFT methods and compared with X-ray structural data in order to evaluate the preferential trioxane ring conformational orientation.