Chiral Silver Phosphate Catalyzed Transformation of ortho‐Alkynylaryl Ketones into 1H‐Isochromene Derivatives through an Intramolecular‐Cyclization/Enantioselective‐Reduction Sequence |
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| Authors: | Prof?Dr Masahiro Terada Feng Li Dr Yasunori Toda |
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| Institution: | 1. Department of Chemistry, Graduate School of Science, Tohoku University, Aramaki, Aoba‐ku, Sendai 980‐8578 (Japan) http://www.orgreact.sakura.ne.jp/index.html;2. Research and Analytical Center for Giant Molecules, Graduate School of Science, Tohoku University, Aramaki, Aoba‐ku, Sendai 980‐8578 (Japan) |
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| Abstract: | 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‐oxabicyclo3.3.1]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. |
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| Keywords: | asymmetric catalysis cyclization enantioselective reduction isobenzopyrylium ions silver salts |
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