La Manna Pellegrino, Soriente Annunziata, De Rosa Margherita, Buonerba Antonio, Talotta Carmen, Gaeta Carmine, Neri Placido
Dipartimento di Chimica e Biologia "A. Zambelli", Università di Salerno, Via Giovanni Paolo II, Fisciano (SALERNO), 84084, Italy.
ChemSusChem. 2019 Apr 23;12(8):1673-1683. doi: 10.1002/cssc.201900137. Epub 2019 Mar 19.
Metal-free Friedel-Crafts benzylation (FCB) of scarcely reactive arenes and heteroarenes was performed under on-water conditions by an environmentally sustainable procedure. The catalytic strategy exploits the hydrophobicity of the resorcinarene macrocycle 1 a. The proposed mechanism is based on the activation of benzyl chloride by H-bonding interactions with catalyst 1 a. In fact, under on-water conditions the hydrophobic amplification of the strength of the H-bonding interactions between the OH groups of the resorcinarene catalyst and the chlorine atom of benzyl chloride leads to polarization of the C-Cl bond, which consequently promotes electrophilic attack of the π nucleophile. Thus, many arenes and heteroarenes were efficiently benzylated under mild on-water conditions by using resorcinarene 1 a as catalyst. The FCB of benzene is industrially relevant for the synthesis of diphenylmethane, and hence the on-water procedure was extended to the gram-scale synthesis of diphenylmethane, starting from benzene and benzyl chloride in the presence of resorcinarene catalyst 1 a.
在水相条件下，通过环境可持续的方法实现了难反应芳烃和杂芳烃的无金属傅克苄基化反应（FCB）。该催化策略利用了间苯二酚芳烃大环化合物1a的疏水性。所提出的机理基于苄基氯通过与催化剂1a的氢键相互作用而被活化。实际上，在水相条件下，间苯二酚芳烃催化剂的羟基与苄基氯的氯原子之间氢键相互作用强度的疏水增强导致C-Cl键极化，从而促进了π亲核试剂的亲电进攻。因此，使用间苯二酚芳烃1a作为催化剂，许多芳烃和杂芳烃在温和的水相条件下都能有效地进行苄基化反应。苯的FCB反应在工业上与二苯甲烷的合成相关，因此该水相方法被扩展到从苯和苄基氯出发，在间苯二酚芳烃催化剂1a存在下进行二苯甲烷的克级合成。
