Nickel-catalyzed remote and proximal Wacker-type oxidation

Abstract

Wacker oxidation chemistry is widely applied to oxidation of olefins to carbonyls in the synthesis of pharmaceuticals, natural products, and commodity chemicals. However, in this chemistry efficient oxidation of internal olefins and highly selective oxidation of unbiased internal olefins without reliance upon suitable coordinating groups have remained significant challenges. Here we report a nickel-catalyzed remote Wacker-type oxidation where reactions occur at remote and less-reactive sp3 C–H sites in the presence of a priori more reactive ones through a chain-walking mechanism with excellent regio- and chemo- selectivity. This transformation has attractive features including the use of ambient air as the sole oxidant, naturally-abundant nickel as the catalyst, and polymethylhydrosiloxane as the hydride source at room temperature, allowing for effective oxidation of challenging olefins. Notably, this approach enables direct access to a broad array of complex, medicinally relevant molecules from structurally complex substrates and chemical feedstocks.