Polystyrene or Magnetic Nanoparticles as Support in Enantioselective Organocatalysis? A Case Study in Friedel–Crafts Chemistry

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• 作者：Sara Ranjbar ; Paola Riente ; Carles Rodríguez-Escrich ; Jagjit Yadav ; Kishore Ramineni ; Miquel A. Pericàs
• 刊名：Organic Letters
• 出版年：2016
• 出版时间：April 1, 2016
• 年：2016
• 卷：18
• 期：7
• 页码：1602-1605
• 全文大小：312K
• ISSN：1523-7052

文摘

Heterogenized versions of the second-generation MacMillan imidazolidin-4-one are described for the first time. This versatile organocatalyst has been supported on 1% DVB Merrifield resin and Fe<sub>3sub>O<sub>4sub> magnetic nanoparticles through a copper-catalyzed alkyne–azide cycloaddition (CuAAC) reaction. The resulting catalytic materials have been successfully applied to the asymmetric Friedel–Crafts alkylation of indoles with α,β-unsaturated aldehydes. While both catalytic systems can be easily recovered and admit repeated recycling, the polystyrene-based catalyst shows higher stability and provides better stereoselectivities.