Oxidative cyclization of dienes and polyenes mediated by transition-metal-oxo species

During the last forty years several groups have reported results concerning the oxidative cyclization of polyenes, mostly dienes, with transition metal oxo species such as MnO4-, RuO4, RuO4- and OsO4 but only recently a systematic study of some of these processes has been undertaken. The formation in a single step of THF, poly-THF, THP and oxepane products with complete relative stereocontrol, and the unique postulated mechanisms, render these processes very appealing both from a synthetic and theoretical point of view. Recent synthetic applications of these oxidative transformations have highlighted their usefulness. The present review summarizes the state of the art in the field trying to provide a comprehen-sive view of these processes. Some similarities between the chemistry of RuO4 and Re (VII) oxo-species are highlighted.