Desymmetrization of 1,4‐Pentadien‐3‐ol by the Asymmetric 1,3‐Dipolar Cycloaddition of Azomethine Imines |
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Authors: | Mari Yoshida Naotaro Sassa Tomomitsu Kato Dr Shuhei Fujinami Dr Takahiro Soeta Prof?Dr Katsuhiko Inomata Prof?Dr Yutaka Ukaji |
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Institution: | Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920‐1192 (Japan), Fax: (+81)?76‐264‐5742 |
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Abstract: | Desymmetrization of the divinyl carbinol 1,4‐pentadien‐3‐ol was accomplished by the asymmetric 1,3‐dipolar cycloaddition of azomethine imines based on a magnesium‐mediated, multinucleating chiral reaction system utilizing diisopropyl (R,R)‐tartrate as the chiral auxiliary. The corresponding optically active trans‐pyrazolidines, each with three contiguous stereogenic centers, were obtained with excellent regio‐, diastereo‐, and enantioselectivity, with results as high as 99 % ee. This reaction was shown to be applicable to both aryl‐ and alkyl‐substituted azomethine imines. The use of a catalytic amount of diisopropyl (R,R)‐tartrate was also effective when accompanied by the addition of MgBr2. |
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Keywords: | azomethine imines cycloaddition desymmetrization diisopropyl tartrate pyrazolidines |
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