Chiral-Boron-Complex Catalyzed Asymmetric Inverse-Electron-Demand Aza-Diels–Alder Reaction of β-Trifluoromethyl α,β-Unsaturated Ketones with Cyclic N-Sulfonyl Ketimines

A highly efficient asymmetric inverse-electron-demand aza-Diels–Alder reaction of β-trifluoromethyl α,β-unsaturated ketone with cyclic N-sulfonyl ketimines catalyzed by (R)-3,3′-I2-BINOL-boron-complex was developed. A broad range of fused piperidine derivatives bearing stereogenic carbon containing CF3 motifs were prepared in high yields with excellent diastereo- and enantioselectivities (up to >20:1 dr, and >99% ee). This protocol had the characteristics of mild reaction conditions, high efficiency, and high stereoselectivity.