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Synfacts 2007(4): 0396-0396  
DOI: 10.1055/s-2007-968359
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Enantioselective Ring Expansion of Methylenecyclopropane Carboxamides

Contributor(s): Hisashi Yamamoto, Matthew B. Boxer
C. Taillier, M. Lautens*
University of Toronto, Canada
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Publication History

Publication Date:
23 March 2007 (online)

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Significance

A nice approach for enantioselective ring expansion of monoactivated methylene­cyclopropanes has been developed. The use of MgI2 as Lewis acid starting material and CP-IndaBOX as chiral ligand afforded the best results, giving adducts in the range of 49-86% ee. Of the tested imine substrates, electron-withdrawing groups on the aryl ring succeeded in yielding higher selectivities than substrates with strongly electron-donating groups.