Highly Selective Synthesis of Pillar[<i>n</i>]arene (<i>n</i> = 5, 6)
作者:Saber Mirzaei、Denan Wang、Sergey V. Lindeman、Camille M. Sem、Rajendra Rathore
DOI:10.1021/acs.orglett.8b02937
日期:2018.10.19
toward the preparation of pillar[n]arenes (n = 5, 6) is reported, based upon a high solvent-dependent selectivity found in the condensation reaction between 1,4-dialkyloxybenzene and paraformaldehyde, involving methanesulfonic acid as catalyst. Pillar[6]arene (P6) is obtained as the major product when using chloroform as solvent, while in dichloromethane pillar[5]arene (P5) is the dominant product. Accordingly
DIBPillar[n]arenes (n = 5, 6) were synthesized. They showed different host−guest properties with n-octyltriethyl ammonium hexafluorophosphate G due to their different cavity sizes. DIBpillar[5]arene showed no complexation with G, while DIBpillar[6]arene formed a 1:1 complex with G with an association constant of 334 (±24) M−1 in chloroform. In this letter, the first pillar[6]arenecrystalstructure and the
facile method for the selective synthesis of pillar[6]arenes has been developed. Due to a strong electron donor‐acceptor interaction between the electron‐deficient naphthalenediimide and a precursor for the pillararene, 1,4‐diisobutoxy‐2,5‐bis(methoxymethyl) benzene, naphthalenediimide has been demonstrated to act as a template for selective synthesis of pillar[6]arene in a modest yield (30%).