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'-I 2 -BINOL-boron-complex was developed. A broad range of fused piperidine derivatives bearing stereogenic carbon containing CF 3 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.