Palladium-Catalyzed Nucleophilic Reaction of Alkylidenecyclopropanes with β,γ-Unsaturated α‑Ketoesters: Ligand-Controlled Divergent Synthesis

A palladium-catalyzed ligand-controlled selective 1,4-addition
and cycloaddition reaction of β,γ-unsaturated α-ketoesters
with alkylidenecyclopropanes (ACPs) has been developed. Using ACPs
and β,γ-unsaturated α-ketoesters as starting materials,
γ-dienyl-α-ketoesters and dihydro-2H-pyrans
could be prepared selectively by modulating the ligand. A range of
multisubstituted α-ketoesters and dihydro-2H-pyrans were obtained in moderate to excellent yields with excellent
regioselectivities.