Asymmetric palladium-catalyzed decarboxylative [3 + 2] cycloaddition: straightforward construction of chiral spiro-heterocyclic scaffolds

We developed an asymmetric Pd-catalyzed [3 + 2] cycloaddition of α,β-unsaturated pyrazolones with vinylethylene carbonates. An array of spiro-tetrahydrofuran-pyrazolones were obtained in high yields with excellent enantioselectivities.