Copper(I)-Catalyzed Oxyamination of β,γ-Unsaturated Hydrazones: Synthesis of Dihydropyrazoles

An efficient aerobic copper(I)-catalyzed oxyamination of β,γ-unsaturated hydrazones has been developed. The methodology provides effective access to dihydropyrazole derivatives in a one-pot process utilizing dioxygen as a sustainable sacrificial oxidant. Mechanistic studies have been performed and are suggestive of an aerobic manifold via single electron transfer.