Synfacts 2011(1): 0046-0046  
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

Rezensent(en):Hisashi Yamamoto, Patrick Brady
T. 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  
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Publikationsverlauf

Publikationsdatum:
21. Dezember 2010 (online)


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.