Chiral-Boron-Complex Catalyzed Asymmetric Inverse-ElectronDemand Aza-Diels-Alder Reaction of -Trifluoromethyl ,-Unsaturated Ketones with Cyclic N-Sulfonyl Ketimines

A highly efficient asymmetric inverse-electron-demand aza-Diels-Alder reaction of beta-trifluoromethyl alpha,beta-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 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.