Dramatic Improvement of the Enantiomeric Excess in the Asymmetric Conjugate Addition Reaction Using New Experimental Conditions
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- 18 April 2002
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 124 (19) , 5262-5263
- https://doi.org/10.1021/ja025598k
Abstract
The asymmetric conjugate addition of dialkylzincs is usually performed with Cu(OTf)2 in toluene. We show that by using a copper carboxylate in Et2O, THF, or EtOAc, we strongly improve the enantioselectivity with a given ligand. Ee values up to 99.1% could be reached with new ligands based on the induced atropisomerism of a simple biphenol unit. In addition, we show that the Lewis acid effect of Cu(OTf)2 is not a significant.Keywords
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