Asymmetric Diels-Alder Cycloadditions of Trifluoromethylated Dienophiles Under Trienamine Catalysis

摘要

beta-Trifluoromethyl (CF3) enones were proved to act as good dienophiles in asymmetric normal-electron-demand Diels-Alder cycloadditions with 2,4-dienals under trienamine catalysis with a chiral secondary amine. The sequential reductive amination transformations with benzylamine produced cis-and trans-fused chiral trifluoromethylated octahydroisoquinolines in a diastereodivergent manner by using NaBH(OAc)(3) and NaBH3CN as the reductants, respectively. Moreover, other types of activated alkenes that bear a CF3 group have also been successfully utilized to construct a diverse range of chiral cyclic frameworks in high stereoselectivity.