Z-Selective Synthesis of γ,δ-Unsaturated Ketones via Pd-Catalyzed Ring Opening of 2-Alkylenecyclobutanones with Arylboronic Acids.

Pd-catalyzed 1,2-addition (instead of 1,4-addition) of arylboronic acids to 2-alkylenecyclobutanones followed by β-carbon elimination from the resulting palladium cyclobutanolates to afford γ,δ-unsaturated ketones was developed. The desired γ,δ-unsaturated ketones were obtained in good to excellent yields with Z/E selectivities of up to >99:1 and a broad spectrum of functional group tolerability.