Rhodium-Catalyzed Ring-Opening Hydroacylation of Alkylidenecyclopropanes with Chelating Aldehydes for the Synthesis of γ,δ-Unsaturated Ketones.

The first intermolecular ring-opening hydroacylation of alkylidenecyclopropanes with chelating aldehydes through a rhodium-catalyzed acrylamide-promoted protocol is reported. This highly efficient catalytic system enables the direct synthesis of a diverse range of linear γ,δ-unsaturated ketones. Good functional group compatibility is demonstrated for the completely atom-economical and remarkably selective proximal C-C bond cleavage process. Mechanistic studies reveal that the bidentate coordination of N,N-dimethylmethacrylamide (L1) to the acylrhodium intermediates might facilitate the cyclopropane ring fragmentation and isomerization.