Enantiodivergent Brucine Diol‐Catalyzed 1,3‐Dipolar Cycloaddition of Azomethine Ylides with α,β‐Unsaturated Ketones

Enantiodivergent catalyst systems were developed using metals with different ionic radii and a multifunctional brucine diol (BD) ligand. The catalytic use of purported 1:1 Cu‐BD complexes in the 1,3‐dipolar cycloaddition of azomethine ylides with chalcones resulted in the selective formation of endo ‐pyrrolidines in 87–96% ee s with an absolute stereochemical outcome of (2 R ,3 S, 4 R, 5 S ). In contrast, an opposite absolute stereochemical outcome was observed by using the catalysts derived from Ag(I) salts and BD. The demonstration of enantiodivergent approaches to a broad class of substrates/reaction types underlines their synthetic value in asymmetric synthesis.