Acetoxy-Peroxyacetals: A Peroxycarbenium Precursor for the Synthesis of Hydroperoxides and Endoperoxides

Herein is examined the reactivity of acetoxy-peroxyacetals as a new source of acyclic peroxycarbenium species. Their reactivity was explored with Sc(OTf)₃, a mild Lewis acid that promotes peroxycarbenium species. The resilience of the tert-butyldimethylsilyl group on peroxyl function was found superior for substitution reactions, enabling the additions of neutral nucleophiles such as enoxysilanes, silylcyanides, silylazides, and allylsilanes. Formal [3 + 2] cycloaddition proceeds specifically with allyltrimethylsilane, depending on several parameters. Peroxysilanes were ultimately transformed into 1,2-dioxolanes or 1,2-dioxanes in a few steps, thanks to the promotion of a second peroxycarbenium ion, which constitutes a new approach to the synthesis of endoperoxides.