Ozone as an Oxygen Source for Alkene Ene-Reactions

Article abstract of DOI:10.1007/BF00811760

A strategy was developed which uses the adduct of ozone and triphenyl phosphite as a substitute for photochemically generated singlet oxygen in ene reactions of olefins.The resulting allylic hydroperoxide can be conveniently reduced by a second mole of phosphite to yield the corresponding allylic alcohol.The aryl phosphate produced as the by-product can either be recycled by reduction or used itself as a commodity.As an example, the two key steps of the rose oxide synthesis involving singlet oxygen can thus be reduced to a one pot procedure.With respect to the reaction mechansim, additional arguments for the direct reaction of the olefin with the phoshite ozonide were gathered.A simple decomposition of the ozonide to produce singlet oxygen was made rather unlikely. - Keywords: Ene reaction; Phosphite ozonide; Organic phosphate; Rose oxide.