A novel ketal fragmentation with aluminium iodide

Abstract

Aluminium iodide, prepared from dry aluminium foil and iodine, in acetonitrile is shown to convert bicyclic ketals in the 6,8-dioxabicyclo[3.2.1]octane series into a cyclohexenone and a substituted pyridine in one step. Details of the structural analysis are discussed. The role of the 1,5-diketone as intermediate for the formation of the cyclohexenone and the pyridine from the bicyclic ketal was secured by subjecting the isolated diketone to various reaction conditions.