Three-Component Asymmetric Mannich Reaction Catalyzed by a Lewis Acid with Rhodium-Centered Chirality

A highly efficient direct asymmetric three-component Mannich reaction of an N-acylpyrazole, an aldehyde and a primary or secondary amine, was enabled by a rhodium-based Lewis-acid catalyst with metal-centered chirality. Excellent enantioselectivities were achieved for a variety of substrates at a typical catalyst loading of merely 0.5mol% (23examples, up to 98% ee).