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Chiral Silver Phosphate Catalyzed Transformation of ortho-Alkynylaryl Ketones into 1H-Isochromene Derivatives through an Intramolecular-Cyclization/Enantioselective-Reduction Sequence


  • This research was partially supported by a Grant-in-Aid for Scientific Research on Innovative Areas “Advanced Molecular Transformations by Organocatalysts” from MEXT (Japan) and a Grant-in-Aid for Scientific Research (Grant No. 23655077) from the JSPS. We gratefully acknowledge Prof. T. Iwamoto and Prof. S. Ishida (Graduate School of Science, Tohoku University) for their kind assistance with X-ray crystallographic analysis. We also thank the JSPS for a research fellowship for Young Scientists (Y.T.).


The transformation of ortho-alkynylaryl ketones through a cyclization/enantioselective-reduction sequence in the presence of a chiral silver phosphate catalyst afforded 1H-isochromene derivatives in high yield with fairly good to high enantioselectivity. An asymmetric synthesis of the 9-oxabicyclo[3.3.1]nona-2,6-diene framework, which has been found in some biologically active molecules, is presented as a demonstration of the synthetic utility of this method.