Recommanded Product: Ethyl 2,3,4,5,6-pentafluorobenzoateOn October 3, 2012 ,《π-π Interaction Assisted Hydrodefluorination of Perfluoroarenes by Gold Hydride: A Case of Synergistic Effect on C-F Bond Activation》 was published in Journal of the American Chemical Society. The article was written by Lv, Hongbin; Zhan, Jin-Hui; Cai, Yuan-Bo; Yu, Yi; Wang, Bingwu; Zhang, Jun-Long. The article contains the following contents:
“”Synergistic effect”” is prevalent in natural metalloenzymes in activating small mols., and the success has inspired the development of artificial catalysts capable of unprecedented organic transformations. In this work, we found that the attractive π-π interaction between organic additives (as electron-donors) and the perfluorinated arenes (as electron acceptors) is effective in gold hydride catalyzed activation of C-F bonds, specifically hydrodefluorination (HDF) of perfluoroarenes catalyzed by the Sadighi’s gold hydrides [(NHC)AuH] (NHC = N-heterocyclic carbene). Although a weak interaction between [(NHC)AuH] and perfluoroarenes was observed from 1H NMR and UV-vis spectroscopies, low reactivity of [(NHC)AuH] toward HDF was found. In contrast, in the presence of p-N,N-dimethylaminopyridine (DMAP), the HDF of perfluoroarenes with silanes can be efficiently catalyzed by [(NHC)AuH], resulting in mainly the para-hydrodefluorinated products with up to 90% yield and 9 turnovers. The yield of the reaction increases with the more electron-withdrawing groups and degree of fluorination on the arenes, and the HDF reaction also tolerates different function groups (such as formyl, alkynyl, ketone, ester, and carboxylate groups), without reduction or hydrogenation of these function groups. To reveal the role of DMAP in the reactions, the possible π-π interaction between DMAP and perfluoroarenes was suggested by UV-vis spectral titrations, 1H NMR spectroscopic studies, and DFT calculations Moreover, 1H and 19F-NMR studies show that this π-π interaction promotes hydrogen transfer from [(NHC)AuH] to pyridyl N atom, resulting in C-F bond cleavage. The interpretation of π-π interaction assisted C-F activation is supported by the reduced activation barriers in the presence of DMAP (31.6 kcal/mol) than that in the absence of DMAP (40.8 kcal/mol) for this reaction. An anal. of the charge distribution and transition state geometries indicate that this HDF process is controlled by the π-π interaction between DMAP and perfluoroarenes, accompanied with the changes of partial at. charges. In the experimental materials used by the author, we found Ethyl 2,3,4,5,6-pentafluorobenzoate(cas: 4522-93-4Recommanded Product: Ethyl 2,3,4,5,6-pentafluorobenzoate)
Ethyl 2,3,4,5,6-pentafluorobenzoate(cas: 4522-93-4) belongs to esters. They are important in biology, being one of the main classes of lipids and comprising the bulk of animal fats and vegetable oils.Recommanded Product: Ethyl 2,3,4,5,6-pentafluorobenzoate They perform as high-grade solvents for a broad array of plastics, plasticizers, resins, and lacquers, and are one of the largest classes of synthetic lubricants on the commercial market. Polyesters are important plastics, with monomers linked by ester moieties.
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