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
pillar[5]arene derivatives with alkyl groups of different length were synthesized. The new alkyl-substituted pillar[5]arene derivatives 1,4-bis(ethoxy)pillar[5]arene (C2), 1,4-bis(propoxy)pillar[5]arene (C3), 1,4-bis(butoxy)pillar[5]arene (C4), 1,4-bis(pentyloxy)pillar[5]arene (C5), 1,4-bis(hexyloxy)pillar[5]arene (C6), and 1,4-bis(dodecanoxy)pillar[5]arene (C12) were obtained by Lewis acid-catalyzed condensation
合成了一系列具有不同长度的烷基的支柱[5]芳烃衍生物。新的烷基取代的支柱[5]芳烃衍生物1,4-双(乙氧基)支柱[5]芳烃(C2),1,4-双(丙氧基)支柱[5]芳烃(C3),1,4-双(丁氧基)立柱[5]芳烃(C4),1,4-双(戊氧基)立柱[5]芳烃(C5),1,4-双(己氧基)立柱[5]芳烃(C6)和1,4通过路易斯酸催化二烷氧基苯单体与低聚甲醛的缩合反应制得双(十二烷氧基)支柱[5]芳烃(C12)。通过动态支柱[5]芳烃衍生物的构象特性进行研究11 H NMR测量。当烷基取代基比甲基大时,柱[5]芳烃中酚单元的旋转受到抑制,其构象被固定。随着它们的长度增加,烷基取代基堆积在上下边缘,从而降低了柱[5]芳烃的构象自由度。
Hybrid [<i>n</i>]Arenes through Thermodynamically Driven Macrocyclization Reactions
experiment, involving pillar[5]arene and per-O-methylated resorcin[4]arene. The scrambling experiment has given hybrid macrocycles in yields comparable with those obtained in condensation reactions. NMR spectra and X-ray structures of hybrid [n]arenes indicate that 1,2- and 1,3-dialkoxybenzene units are flexible parts of macrocyclic rings. However, the 1,4-dialkoxybenzene units present considerable
杂化[ n ]芳烃是由不同的烷氧基苯单元组成的一类中型大环化合物,是通过布朗斯台德酸(三氟乙酸)催化的两个不同的烷氧基苯与甲醛的简单的一锅直接缩合而获得的。我们已经表明,在布朗斯台德酸催化下,该反应是可逆的,因此受产物的相对稳定性支配。主要的大环产物是杂种[ n由四个[2 + 2]或[3 +1]化学计量的烷氧基苯单元组成的芳烃。然而,作为1,4-二甲氧基苯,1,3,5-三甲氧基苯和甲醛之间缩合的主要产物,也获得了一个不寻常的[3 + 2]杂化大环。杂化产物的稳定性和反应的可逆性通过加扰实验得到了进一步证实,该实验涉及柱[5]芳烃和过-O-甲基化间苯二酚[4]芳烃。加扰实验给出了杂化大环化合物,其产率可与缩合反应获得的产率相媲美。杂种[ n芳烃表明1,2-和1,3-二烷氧基苯单元是大环的柔性部分。然而,1,4-二烷氧基苯单元存在相当大的空间位阻,由于抑制了旋转,导致形成异构体和固有的手性大环
Synthesis and host-guest properties of pillar[6]arenes
the synthesis of pillar[6]arenes was developed. A series of pillar[6]arenes were prepared with FeCl3 as catalyst and chloroform as solvent at room temperature in moderate yields (30%–40%). Their host-guest properties with n-cetyltrimethyl ammonium bromide were investigated by 1 HNMR. The results showed that high selectivity in the host-guest relationship became apparent between pillar[6]arenes and
One-pot synthesis of pillar[n]arenes catalyzed by a minimum amount of TfOH and a solution-phase mechanistic study
作者:Kai Wang、Li-Li Tan、Dai-Xiong Chen、Nan Song、Guan Xi、Sean Xiao-An Zhang、Chunju Li、Ying-Wei Yang
DOI:10.1039/c2ob26635k
日期:——
A practical and effective trifluoromethanesulfonicacid (TfOH)-catalyzed cyclooligomerization strategy was developed for the synthesis of functionalized pillar[n]arenes and copillar[5]arenes from 1,4-dialkoxybenzenes with paraformaldehyde under mild reaction conditions, and the reaction mechanism of solution-phase catalytic synthesis of pillararenes was investigated by room-temperature X-band ESR spectroscopy
实用有效 三氟甲磺酸 (三氟乙酸)在温和的反应条件下,开发了由1,4-二烷氧基苯与多聚甲醛合成官能化的柱[ n ]芳烃和copillar [5]芳烃的)催化环寡聚反应策略,并研究了溶液相催化合成柱芳烃的反应机理通过室温X波段ESR光谱,质谱,NMR和对照实验,表明最初的自由基过程以及随后的偶联和闭环阶段的Friedel-Crafts烷基化过程。