Oxidative cleavage of cycloalkanones with dioxygen catalyzed by supported catalysts or homogeneous systems: Evidence for novel active ruthenium (II) and/or (III) species

α-Substituted cycloalkanones are oxidized to oxo-acids by low-nuclearity complexes (Cu2+ or [VO2]+/[VO]2+ – exchanged Nafion® beads), or homogeneous systems with ruthenium acetate complexes and [Ru(H2O)6] (tosylate)2 in dioxygen (0.1 MPa) at 55–60 °C. The catalytic procedures compare well with previously described systems involving homogeneous catalysis with copper (II) or polyoxometalates such as “H8[PMo7V5O40]·aq”. The results complement the widely used oxidative methods for ketone cleavage in cases when protons and transition metal salts are involved. A tentative dioxygenase mechanism, involving peroxygen species, is proposed for these reactions.

Figure optionsDownload high-quality image (23 K)Download as PowerPoint slideResearch highlights▶ Selective oxidation by a homogeneous ruthenium (III/II) system and dioxygen. ▶ Dioxygen as the terminal oxidant. ▶ The Ru(III)/Ru(II) system activate dioxygen and oxidize cycloalkanones to keto-acids. ▶ A tentatively assigned dioxygenase mechanism involving peroxygen species.