Advances in the Organocatalytic Asymmetric Mannich Reaction of Six-Membered Unsaturated Heterocycles: Methodology and Application

The organocatalytic asymmetric Mannich reaction has always been an area of active interest in the community of chemistry. The Mannich products, optically active beta-amino-carbonyl compounds, can be used as important intermediates for biologically active molecules. Compared with the well-researched acyclic imines, the organocatalytic asymmetric Mannich reactions of cyclic unsaturated substrates have been on the rise in recent years, which provide an exciting platform for the construction of various enantioenriched nitrogen-containing polyheterocycles. In this minireview, we will summarize the advances in the field of organocatalytic asymmetric Mannich and related reactions, including decarboxylative Mannich reactions and Mannich involved cascade processes of six-membered unsaturated heterocycles, and their applications in the synthesis of natural products and pharmaceuticals.