which was compatible with a metal-catalyzed reaction in spite of donating and oxidizable sulfur atoms. Metal-catalysis with a persulfurated aromatic ligand was demonstrated for the first time in a model reaction: the Rh-enantioselective hydrosilylation of acetophenone. The interesting features were the reactivity and the enantiocatalytic behavior while varying the metal content. This work promotes new thoughts
and wide scope in aromatic and heteroaromatic chemistry are presented. Exchange of sulfur components surrounding arenes and heteroarenes may occur at 25 °C, in a process that one may call a “sulfur dance”. A dynamic covalent system involving four components illustrates the thermodynamically-driven formation of a thiacalix[2]arene[2]pyrimidine. This work stimulates the implementation of reversible SNAr
鉴于一类可逆亲核芳香族取代反应在芳香族和杂芳族化学中的重要性和广泛范围,提出了它们的特征。芳烃和杂芳烃周围的硫成分交换可能在 25 °C 时发生,这一过程可以称为“硫舞”。涉及四个组分的动态共价系统说明了噻卡利克斯[2]芳烃[2]嘧啶的热力学驱动形成。这项工作刺激了可逆 SNAr 反应在有机、材料和共价动态化学中的实施。
Tucker, James H. R.; Gingras, Marc; Brand, Holger, Journal of the Chemical Society. Perkin transactions II, 1997, # 7, p. 1303 - 1308
作者:Tucker, James H. R.、Gingras, Marc、Brand, Holger、Lehn, Jean-Marie
DOI:——
日期:——
Polyvalent Interactions in Unnatural Recognition Processes
作者:James N. Lowe、David A. Fulton、Sheng-Hsien Chiu、Arkadij M. Elizarov、Stuart J. Cantrill、Stuart J. Rowan、J. Fraser Stoddart
DOI:10.1021/jo030283o
日期:2004.6.1
The synthesis of two cluster compounds, one containing six secondary dialkylammonium ion centers and the other possessing six benzo-m-phenylene[25]crown-8 (BMP25C8) macrocycles, both appended to hexakis(thiophenyl)benzene cores, is described. The binding of these clusters with complementary mono- and divalent ligands is investigated with NMR spectroscopy to probe polyvalency in these unnatural recognition systems. The ability of the two different families of clusters to bind complementary monovalent ligands is compared with that of the monovalent receptor pair, namely the dibenzylammonium ion and BMP25C8. This comparison is made possible by determining an average association constant (K-AVE) for the binding of each recognition site on the cluster with the corresponding monovalent ligand. We have found that the clustering of recognition sites together in one molecule is detrimental to their individual abilities to bind monovalent ligands. In the case of the polyvalent interaction between the hexakisBMP25C8 cluster and divalent dialkylammonium ions, an association constant, K-POLY, was calculated from the value of K-AVE determined for the complexation of the individual component recognition sites. This polyvalent interaction is significantly stronger than that associated with the averaged monovalent interactions.