A Redox-Reconfigurable, Ambidextrous Asymmetric Catalyst

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• 作者：Shahab Mortezaei ; Noelle R. Catarineu ; James W. Canary
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：May 16, 2012
• 年：2012
• 卷：134
• 期：19
• 页码：8054-8057
• 全文大小：258K
• 年卷期：v.134,no.19(May 16, 2012)
• ISSN：1520-5126

文摘

A redox-reconfigurable catalyst derived from l-methionine and incorporating catalytic urea groups has been synthesized. This copper complex catalyzes the enantioselective addition of diethyl malonate to trans-尾-nitrostyrene. Either enantiomer of the product can be predetermined by selection of the oxidation state of the copper ion. Enantiomeric excesses of up to 72% (S) and 70% (R) were obtained in acetonitrile. The ability of the catalyst to invert enantiomeric preference was reproduced with several different solvents and bases. Facile interconversion between the Cu²⁺ and Cu⁺ redox states allowed easy access to both active helical forms of the complex and, therefore, dial-in enantioselectivity.