Aldehyde Deformylation and Catalytic C-H Activation Resulting from a Shared Cobalt(II) Precursor

The tetradentate ligand N,N'-dibenzyl-N,N'-bis(2-pyridylmethyl)-1,2-cyclohexanediamine (bbpc) was used to prepare cobalt(II) diacetonitrilo and cobalt(III) peroxo complexes, the latter of which was structurally characterized. The cobalt(III) peroxo compound forms from reactions between the cobalt(II) complex, hydrogen peroxide, and a base, and it stoichiometrically reacts with aldehydes to yield mixtures of alkenes and ketones. The cobalt(II) precursor is capable of catalyzing the activation of weak C-H bonds by either iodosobenzene or m-chloroperbenzoic acid. This chemistry differs from most previously characterized cobalt-mediated C-H activation in that (1) it is catalytic, rather than stoichiometric, with respect to the cobalt and (2) it does not need a second Lewis acid metal ion in order to proceed.