Relay Catalysis Using a Rhodium Complex/Chiral Brønsted Acid Binary System: Enantioselective Reduction of a Carbonyl Ylide as the Reactive Intermediate


  • This work was partially supported by the Japan Society for the Promotion of Science (JSPS) through a Grant-in-Aid for Scientific Research (Grant No. 23655077)), a Grant-in-Aid for Scientific Research on Innovative Areas “Advanced Molecular Transformations by Organocatalysts” from the MEXT (Japan), and the Uehara Memorial Foundation. We gratefully acknowledge Prof. Shunichi Hashimoto (Hokkaido University) for providing the chiral dirhodium(II) tetracarboxylate complexes 1 d and 1 e. We also thank JSPS for a research fellowship for Young Scientists (Y.T.).


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Pass the baton: A one-pot relay catalysis for a carbonyl ylide formation/enantioselective reduction sequence using a dirhodium(II) tetracarboxylate and chiral phosphoric acid catalyst system is described. The four-step transformation involves a rhodium carbene complex, a carbonyl ylide, and an isobenzopyrylium intermediate, the enantioselective reduction of which yields isochromanone derivatives in good yield with high selectivity.