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Synfacts 2006(4): 0365-0365  
DOI: 10.1055/s-2006-932040
Metal-Catalyzed Asymmetric Synthesis and Stereoselective Reactions
© Georg Thieme Verlag Stuttgart · New York

Asymmetric Cyclopropanation of Styrene with a Cu(I)-Cyclopropyl Bisoxazoline Ligand

Contributor(s): Mark Lautens, Andrew Martins
M. Itagaki*, Y. Yamamoto
Sumitomo Chemical Co., LTD., Osaka and Hiroshima University, Japan
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Publication History

Publication Date:
24 March 2006 (online)

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Significance

The Cu(I)-catalyzed cyclopropanation of styrene with ethyl diazoacetate was examined through the screening of several chiral bis-oxazoline (BOX) ligands. Overall, it was found that the cyclopropyl-BOX ligand gave the best results, affording the products with an unprecedented trans/cis ratio of 84:16 and >99.9% ee for both ­diastereomers. In addition to the excellent selectivities, low catalyst loading and the use of non-chlorinated solvents add to the attractiveness of this method.