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Synfacts 2011(1): 0046-0046
DOI: 10.1055/s-0030-1258988
DOI: 10.1055/s-0030-1258988
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag
Stuttgart ˙ New York
Stereoselective [3+2] Cycloaddition of Imino Esters with Nitroalkenes
Contributor(s):Hisashi Yamamoto, Patrick BradyT. Arai*, N. Yokoyama, A. Mishiro, H. Sato
Chiba University and Rigaku Corporation, Tokyo, Japan
Catalytic Asymmetric exo′-Selective [3+2] Cycloaddition of Iminoesters with Nitroalkenes
Angew. Chem. Int. Ed. 2010, 49: 7895-7898
Chiba University and Rigaku Corporation, Tokyo, Japan
Catalytic Asymmetric exo′-Selective [3+2] Cycloaddition of Iminoesters with Nitroalkenes
Angew. Chem. Int. Ed. 2010, 49: 7895-7898
Further Information
Publication History
Publication Date:
21 December 2010 (online)
Key words
nitroalkenes - 1,3-dipolar cycloaddition - pyrrolidines - nickel
Significance
A library of solid-phase imidazoline-aminophenol/metal catalysts was prepared and a high-throughput screening method employing analysis by circular dichroism spectroscopy was used to find the most selective catalyst. This is the first method to generate exo′ products in high diastereoselectivity and with excellent ee values.
Comment
The exo′ stereochemistry suggests that the mechanism is not a concerted [3+2] cycloaddition. The authors propose a stepwise mechanism that involves 1,4-addition followed by a Mannich-type reaction as shown above.