Organocatalytic Asymmetric Tandem Michael/Cyclization Reaction

Multisubstituted dihydropyrroles bearing a stereogenic center at the 3-position represent an important class of nitrogen heterocycles, which are encountered in a wide range of biologically active natural alkaloids, pharmaceutically active compound optically active 2,3-dihydropyrroles, in particular, can not only be used as a versatile intermediate in the total synthesis of these active compounds but also be readily converted to valuable chiral proline and pyrrolidine derivatives. As such, much effort has been devoted to the synthesis of these privileged heterocyclic motifs. However, to date, the asymmetric catalytic approaches to construct these heterocycles in enan-tiomerically pure form are still surprisingly rare and less exploited. Thus, the development of a fascinating and powerful strategy that allowed the rapid construction of enantioenriched and structurally diverse 2,3-dihydropyrroles is particularly appealing.After careful studys, a unique approach to asymmetric synthesis of various optically pure multisubstituted 2,3-dihydropyrroles catalyzed by a novel rosin-derived tertiary amine-thiourea via a tandem Michael/cyclization sequence with high yield (up to 97%) and good to excellent enantioselectivities (up to 97% ee) is present. This strategy provides an efficient and convenient method to access enantioenriched nitrogen heterocycles.