Construction Of Chiral 4H-chromenes And Tetrahydroquinolines By Cascade Reaction Initiated By Michael Addition

This thesis is composed of two parts.In the first part,A novel organocatalytic cascade process initiated by 1,6-conjugated addition has been successfully developed.A range of pharmaceutically active 2-amino-4-aryl-4H-chromenes were readily obtained in high yields(88%-99%)and excellent enantiopurities(86%-99% ee).The functionalized para-Quinone methides(p-QMs)could be facilely obtained.Meanwhile,an efficient cascade aza-Michael-Michael sequence for the preparation of tetrahydroquinolines has been successfully established.Three contiguous stereogenic centers are created with high levels of enantioselectivities(79-99% ee)and exclusive diastereoselectivities in the presence of a bifunctional squaramide.This approach is compatible with a broad range of ?,?-unsaturated ?-ketoesters and 2-aminochalcones,generating various densely functionalized tetrahydroquinolines.Our protocol indicated that ?-site of ?,?-unsaturated ?-ketoester is an available pro-nucleophilic site,effectively expanding utilizable scope of ?,?-unsaturated ?-ketoester.