Selective formation of heterocyclic <i>trans</i>-cycloalkenes by alkyne addition to a biphenylene-based phosphane/borane frustrated Lewis pair
作者:Jun Li、Constantin G. Daniliuc、Gerald Kehr、Gerhard Erker
DOI:10.1039/c8cc03369b
日期:——
The intramolecular 1-PMes2/8-B(C6F5)2 substituted biphenylene frustratedLewispair 4 shows some behavior reminiscent of intermolecular FLP systems. It undergoes trans-1,2-addition to a series of 1-alkynes to give the respective heterocyclic eight-membered E-alkenes 8. The P/B FLP 4 also reacts with triplet dioxygen to yield the [P]–O–[B](OC6F5) containing oxygenation product.
分子内1-PMes 2 / 8-B(C 6 F 5)2取代的联苯阻抑的路易斯对4显示出一些行为,让人联想到分子间FLP系统。它经历反式-1,2-加成反应生成一系列1-炔烃,得到各自的杂环八元E-烯烃8。P / B FLP 4也与三重态双氧反应生成[P] –O– [ B](OC 6 F 5)含氧合产物。
Facile Synthesis of Aryl- and Alkyl-bis(trifluoromethylsulfonyl)methanes
Various arylbis(trifluoromethylsulfonyl)methanes (1) have been synthesized by reacting the corresponding benzylic halides with sodium trifluoromethanesulfinate and then with triflic anhydride. In addition, when the aryl group of 1 is a pentafluorophenyl group, the nucleophilic para-substitution of the aryl group with alkyllithiums and sodium alkoxides occurs. This reaction is useful for the design of new Brønsted acids.
Through-space interactions between parallel-offset arenes at the van der Waals distance: 1,8-diarylbiphenylene syntheses, structure and QM computations
作者:Franco Cozzi、Rita Annunziata、Maurizio Benaglia、Kim K. Baldridge、Gerardo Aguirre、Jesús Estrada、Yongsak Sritana-Anant、Jay S. Siegel
DOI:10.1039/b800031j
日期:——
A model for studying polar–π interactions between arenes spaced at van der Waals distances is developed on the basis of peri-diarylbiphenylenes. A set of 1,8-diarylbiphenylenes is synthesized comprising two Hammett series, one with reference to mesityl ring interactions and the other with reference to pentafluorophenyl ring interactions. X-Ray crystal structures of several derivatives are determined. Barriers to rotation of the probe aryl ring are derived from dynamic NMR data and show a trend for the mesityl reference series (ΔG≠vs. σ°). The model is also used as a test for comparison of modern density functional methods, including B3LYP, M06-2X and BMK functionals; dispersive effects are seen to be an important factor in the proper theoretical treatment of arene interactions.
Highly Efficient Recognition of Native TpT by Artificial Ditopic Hydrogen-Bonding Receptors Possessing a Conformationally Well-Defined Linkage
作者:Masayoshi Takase、Masahiko Inouye
DOI:10.1021/jo0264473
日期:2003.2.1
Synthesis and binding affinity of rationally designed artificialditopic nucleobase receptors are reported. The ditopicreceptors were designed to recognize thymine-thymine dinucleotides by their two hydrogen-bonding moieties, which are connected to conformationally well-defined linkages such as ferrocene and biphenylene. The ditopicreceptors exhibited a remarkably strong binding affinity for lipophilic
biphenylene) can control the direction of formation of a self-assembled structure. The fine-tuning of the distances between the two amidinium groups in the spacer units can help control the stabilizing interactions of two carboxylic acid units (intermolecular attraction) after the four-component assembly (see Scheme 1). Based on this concept, we succeeded in the formation of a four-component box-like assembled