Cobalt(II)-Salen-Linked Complementary Double-Stranded Helical Catalysts for Asymmetric Nitro-Aldol Reaction

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• 作者：Daisuke Taura ; Shogo Hioki ; Junki Tanabe ; Naoki Ousaka ; Eiji Yashima
• 刊名：ACS Catalysis
• 出版年：2016
• 出版时间：July 1, 2016
• 年：2016
• 卷：6
• 期：7
• 页码：4685-4689
• 全文大小：381K
• 年卷期：0
• ISSN：2155-5435

文摘

Double-helical, bimetallic chiral Co(II)-salen complexes stabilized by chiral amidinium–carboxylate salt bridges efficiently catalyzed the asymmetric nitro-aldol (Henry) reaction, producing products with up to an 89% enantiomeric excess (ee); the reactivity and enantioselectivity were higher than those catalyzed by the corresponding single strands. The key role of the chiral double-helical framework for the supramolecular bimetallic catalysis has been revealed by a double-helical catalyst carrying achiral Co(II)-salen units that promoted the Henry reaction, yielding the product with a 50%–45% ee, while the corresponding single strands showed poor or no enantioselectivity.