Theoretical Investigation of the Mechanism of the Hock rearrangement with InCl3 as Catalyst

The Hock rearrangement is an acid catalyzed reaction involving organic hydroperoxides and resulting in an oxidative cleavage of adjacent C–C bonds. It has significant industrial applications, like the production of phenol (cumene process), but it remains scarcely used in organic synthesis. In addition, its detailed mechanism has never been studied. Thus, we report herein a theoretical study of the Hock rearrangement, using InCl3 as a Lewis acid catalyst. The aim of this work was to fully understand the mechanism of this fundamental reaction, and to rationalize the influence of the substrate electronic properties on the reaction outcome. Furthermore, the structure of the active indium(III) catalyst interacting with the per-oxide substrate was investigated, showing the superiority of a coordinated monomeric form of the Lewis acid as the active catalytic species, compared to dimeric species. However, we show that In2Cl6 species coordinated to the substrate are cen-tral in this catalytic cycle, serving as a reservoir of active monomeric species.