Polarity-Tolerant Chloride Binding in Foldamer Capsules by Programmed Solvent-Exclusion
作者:Yun Liu、Fred C. Parks、Edward G. Sheetz、Chun-Hsing Chen、Amar H. Flood
DOI:10.1021/jacs.0c12562
日期:2021.3.3
geometry and its ability to exclude solvent were supported by solid-state and solution phase studies. This capsule then withstood a 4-fold increase in solvent dielectric constant (εr) from dichloromethane (9) to acetonitrile (36) while maintaining a high and solvent-independent affinity of 105 M–1; ΔG ∼ 28 kJ mol–1. This behavior is unusual. More typical of solvent-dependent behavior, Cl– affinities
在广泛的溶液环境中持久的阴离子结合是一项关键挑战,继续激发并要求合成受体设计中的新策略。尽管在低极性溶剂中的牢固结合已成为常规做法,但我们在高极性溶剂中保持高亲和力的能力尚未达到自然设定的标准。阴离子在水性环境中被蛋白质结合并定期运输,该蛋白质使用二级和三级结构从水中分离出阴离子结合位点。受溶剂排斥原理的启发,我们创建了一个序列定义的foldameric胶囊,该胶囊的整体最小构象显示螺旋折叠状态,并预先进行1:1阴离子络合。固态和溶液相研究支持了折叠后的几何形状的高稳定性及其排除溶剂的能力。r)从二氯甲烷(9)到乙腈(36),同时保持10 5 M –1的高且不依赖溶剂的亲和力;Δ ģ〜28千焦耳摩尔-1。这种现象是不寻常的。更典型的依赖性溶剂行为,氯-亲和力见于对照化合物,如芳基-三唑的大环和五元组直线下降,与易受电介质筛选其暴露于溶剂的结合腔。最后,二甲亚砜通过假定的溶剂结合使折叠剂变性,然后降低折叠剂的Cl
Efficient Synthesis of Aminomethylated Pyrroloindoles and Dipyrrolopyridines via Controlled Copper-Catalyzed Domino Multicomponent Coupling and Bis-cyclization
Efficient methods for the synthesis of pyrrole-fused indole derivatives via domino copper-catalyzed multicomponent coupling and bis-cyclization have been developed. The mono- or bis-aminomethylated pyrroloindoles and dipyrrolopyridines were selectively obtained in moderate to excellent yields by a controlled Mannich-type reaction-cyclization of 4,6-diethynyl-1,3-phenylenediamine or its pyridine congener with paraformaldehyde and a secondary amine. The high-yielding bis-cyclization of terminal alkynes without using Mannich-type reactions is also presented.
Cyclization of Acetylenic Amides Using a Cationic Rhodium(I) Complex
作者:Suzanne Burling、Leslie D. Field、Hsiu L. Li、Barbara A. Messerle、Adelle Shasha
DOI:10.1071/ch04032
日期:——
The cationic Rh(I) dicarbonyl complex [Rh(bim)(CO)2}+BPh4–] 1, containing a bidentate bisimidazolylmethane ligand [bim refers to bis(N-methylimidazol-2-yl)methane] acts as a catalyst for the cyclization of alkynyl amides to produce lactams and N-acyl heterocyclic compounds.