Mechanism of Ni-Catalyzed Oxidations of Unactivated C(sp)-H Bonds.

The Ni-catalyzed oxidation of unactivated alkanes, including the oxidation of polyethylenes, by -chloroperbenzoic acid (CPBA) occur with high turnover numbers under mild conditions, but the mechanism of such transformations has been a subject of debate. Putative, high-valent nickel-oxo or nickel-oxyl intermediates have been proposed to cleave the C-H bond, but several studies on such complexes have not provided strong evidence to support such reactivity toward unactivated C(sp)-H bonds. We report mechanistic investigations of Ni-catalyzed oxidations of unactivated C-H bonds by CPBA.

Palladium-Catalyzed Oxidation of β-C(sp)-H Bonds of Primary Alkylamines through a Rare Four-Membered Palladacycle Intermediate.

Site-selective functionalizations of C-H bonds are often achieved with a directing group that leads to five- or six-membered metallacyclic intermediates. Analogous reactions that occur through four-membered metallacycles are rare. We report a challenging palladium-catalyzed oxidation of primary C-H bonds β to nitrogen in an imine of an aliphatic amine, a process that occurs through a four-membered palladacyclc intermediate.