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

초록

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% ees with an absolute stereochemical outcome of (2R, 3S, 4R, 5S). 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.

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