Constructive Ozonolysis: Capturing Primary Ozonides

Ozonolysis is a widely used and practical synthetic technique for the deconstructive oxidation of olefins using ozone. While there are numerous ozonolysis reactions that give myriad products and functionality, almost all of them involve scission at the olefin double bond. Utilizing ozone as a constructive reagent rather than a deconstructive one would open new domains of chemical reactivity and amplify molecular complexity in synthetic methodology. We report here the first instance of primary ozonides as preparative synthetic intermediates for a safe and green olefin syn-dihydroxylation reaction. Additionally, we have demonstrated this method using a continuous flow reactor that virtually eliminates peroxide accumulation and extended these applications towards the synthesis of pharmaceutically relevant small molecules including guaifenesin, the active ingredient in Mucinex and a precursor to ponesimod, a drug to treat multiple sclerosis.