10565-13-6Relevant articles and documents
Copper(I) Iodide-Catalyzed (Het)arylation of Diethyl Malonate with (Het)aryl Bromides by Using 1,3-Benzoxazole as a Ligand
Zeng, Yu,Zheng, Hao-Liang,Yang, Zhao,Liu, Cheng-Kou,Fang, Zheng,Guo, Kai
, p. 79 - 84 (2018)
An efficient Ullmann-type coupling of aryl bromides with diethyl malonate in the presence of copper(I) iodide and 1,3-benzoxazole is presented. This method has a broad substrate scope (heterocyclic and phenyl bromides) and good functional-group tolerance (OMe, Me, Ac, CN, NO 2, F, and Cl). Moreover, less time is needed to reach full conversion (3-9 hours).
First heterogeneously palladium catalysed α-arylation of diethyl malonate
Djakovitch, Laurent,K?hler, Klaus
, p. 101 - 107 (2000)
Pd exchanged NaY zeolites ([Pd(0)]-, [Pd(II)]- and entrapped [Pd(NH3)4]) exhibit a good activity towards the α-arylation of carbonyl compounds using different para-substituted aryl bromides. Low Pd-concentrations (only 2 mol%) are required to observe interesting activity. The catalysts can easily be separated from the reaction mixture and reused without any loss in activity. For large-scale applications the alternative use of an insoluble base as K2CO3 seems to be promising. The electronic nature of the aryl halides plays a limited role concerning the rate of the reaction.
Nucleophilic Reactivities of 2-Substituted Malonates
Puente, ángel,He, Shanshan,Corral-Bautista, Francisco,Ofial, Armin R.,Mayr, Herbert
, p. 1841 - 1848 (2016)
Kinetics of the reactions of 2-substituted malonate anions and 5-substituted Meldrum's acid anions with benzhydrylium ions and structurally related quinone methides have been monitored in dimethyl sulfoxide solution at 20 °C. The resulting second-order rate constants followed the correlation lg k(20 °C) = sN(E + N), which allowed the nucleophile-specific parameters N and sN to be calculated for these highly stabilized carbanions and to integrate them in our comprehensive nucleophilicity scale. Given that the reactions of the benzhydrylium ions with the anions derived from 5-aryl-substituted Meldrum's acids did not proceed to completion, the corresponding equilibrium constants could be determined. In combination with available data for pyridines and benzoate ions, these equilibrium constants provide a direct comparison of the strengths of C-, N-, and O-centered Lewis bases with respect to C-centered Lewis acids.
Enantioselective Desymmetrization of 2-Aryl-1,3-propanediols by Direct O-Alkylation with a Rationally Designed Chiral Hemiboronic Acid Catalyst That Mitigates Substrate Conformational Poisoning
Estrada, Carl D.,Ang, Hwee Ting,Vetter, Kim-Marie,Ponich, Ashley A.,Hall, Dennis G.
supporting information, (2021/04/07)
Enantioselective desymmetrization by direct monofunctionalization of prochiral diols is a powerful strategy to prepare valuable synthetic intermediates in high optical purity. Boron acids can activate diols toward nucleophilic additions; however, the design of stable chiral catalysts remains a challenge and highlights the need to identify new chemotypes for this purpose. Herein, the discovery and optimization of a bench-stable chiral 9-hydroxy-9,10-boroxarophenanthrene catalyst is described and applied in the highly enantioselective desymmetrization of 2-aryl-1,3-diols using benzylic electrophiles under operationally simple, ambient conditions. Nucleophilic activation and discrimination of the enantiotopic hydroxy groups on the diol substrate occurs via a defined chairlike six-membered anionic complex with the hemiboronic heterocycle. The optimal binaphthyl-based catalyst 1g features a large aryloxytrityl group to effectively shield one of the two prochiral hydroxy groups on the diol complex, whereas a strategically placed "methyl blocker"on the boroxarophenanthrene unit mitigates the deleterious effect of a competing conformation of the complexed diol that compromised the overall efficiency of the desymmetrization process. This methodology affords monoalkylated products in enantiomeric ratios equal or over 95:5 for a wide range of 1,3-propanediols with various 2-aryl/heteroaryl groups.
Method for immobilizing CuI to catalyze active methylene compound arylation by adopting fixed bed microchannel reaction device
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Paragraph 0046; 0047, (2017/08/29)
The invention discloses a method for immobilizing CuI to catalyze active methylene compound arylation by adopting a fixed bed microchannel reaction device. The method comprises the steps of (1) dissolving aryl halide ArX into a first organic solvent; (2) dissolving an active methylene compound, a nitrogen-oxygen polydentate ligand and organic alkali into a second organic solvent; (3) adding a solid catalyst copper iodide to a fixed bed microstructure reactor in the fixed bed microchannel reaction device; and (4) mixing the solution obtained in the step (1) and the solution obtained in the step (2) in a mixer of the microchannel reaction device, pumping the mixed solution into the fixed bed microstructure reactor obtained in the step (3), and collecting an outflow liquid after reaction. The used catalyst and ligand are low in price and easily available. Compared with the same type of reaction in the prior art, the method is short in reaction time and mild in reaction condition and has good application prospect.