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Gutmann's Donor Numbers Correctly Assess the Effect of the Solvent on the Kinetics of SNAr Reactions in Ionic Liquids 下载免费PDF全文
Jazmín Alarcón‐Espósito Prof. Dr. Renato Contreras Prof. Dr. Ricardo A. Tapia Dr. Paola R. Campodónico 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(37):13347-13351
We report an experimental study on the effect of solvents on the model SNAr reaction between 1‐chloro‐2,4‐dinitrobenzene and morpholine in a series of pure ionic liquids (IL). A significant catalytic effect is observed with reference to the same reaction run in water, acetonitrile, and other conventional solvents. The series of IL considered include the anions, NTf2?, DCN?, SCN?, CF3SO3?, PF6?, and FAP? with the series of cations 1‐butyl‐3‐methyl‐imidazolium ([BMIM]+), 1‐ethyl‐3‐methyl‐imidazolium ([EMIM]+), 1‐butyl‐2,3‐dimethyl‐imidazolium ([BM2IM]+), and 1‐butyl‐1‐methyl‐pyrrolidinium ([BMPyr]+). The observed solvent effects can be attributed to an “anion effect”. The anion effect appears related to the anion size (polarizability) and their hydrogen‐bonding (HB) abilities to the substrate. These results have been confirmed by performing a comparison of the rate constants with Gutmann's donicity numbers (DNs). The good correlation between rate constants and DN emphasizes the major role of charge transfer from the anion to the substrate. 相似文献
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Peña-Cabrera E Aguilar-Aguilar A Gonzalez-Domínguez M Lager E Zamudio-Vazquez R Godoy-Vargas J Villanueva-García F 《Organic letters》2007,9(20):3985-3988
An unprecedented synthesis of 8-substituted-borondipyrromethenes is described starting from 8-thiomethylbodipy 1. Aryl, heteroaryl, alkenyl, and organometallic boronic acids smoothly reacted with 1 in the presence of a catalytic amount of Pd(0) and a stoichiometric amount of Cu(I)-2-thienylcarboxylate under neutral conditions to give the corresponding Bodipy analogues in good to quantitative yields (20 examples). A remarkable reactivity was observed in some cases, e.g., ferrocenylboronic acid gave the product in 98% isolated yield after only 10 min at 55 degrees C. 相似文献
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