5668-93-9Relevant academic research and scientific papers
Transition-Metal-Free C-C, C-O, and C-N Cross-Couplings Enabled by Light
Liu, Wenbo,Li, Jianbin,Querard, Pierre,Li, Chao-Jun
, p. 6755 - 6764 (2019/05/06)
Transition-metal-catalyzed cross-couplings to construct C-C, C-O, and C-N bonds have revolutionized chemical science. Despite great achievements, these metal catalysts also raise certain issues including their high cost, requirement of specialized ligands, sensitivity to air and moisture, and so-called "transition-metal-residue issue". Complementary strategy, which does not rely on the well-established oxidative addition, transmetalation, and reductive elimination mechanistic paradigm, would potentially eliminate all of these metal-related issues. Herein, we show that aryl triflates can be coupled with potassium aryl trifluoroborates, aliphatic alcohols, and nitriles without the assistance of metal catalysts empowered by photoenergy. Control experiments reveal that among all common aryl electrophiles only aryl triflates are competent in these couplings whereas aryl iodides and bromides cannot serve as the coupling partners. DFT calculation reveals that once converted to the aryl radical cation, aryl triflate would be more favorable to ipso substitution. Fluorescence spectroscopy and cyclic voltammetry investigations suggest that the interaction between excited acetone and aryl triflate is essential to these couplings. The results in this report are anticipated to provide new opportunities to perform cross-couplings.
Lewis Acid Assisted Nickel-Catalyzed Cross-Coupling of Aryl Methyl Ethers by C-O Bond-Cleaving Alkylation: Prevention of Undesired β-Hydride Elimination
Liu, Xiangqian,Hsiao, Chien-Chi,Kalvet, Indrek,Leiendecker, Matthias,Guo, Lin,Schoenebeck, Franziska,Rueping, Magnus
supporting information, p. 6093 - 6098 (2016/05/19)
In the presence of trialkylaluminum reagents, diverse aryl methyl ethers can be transformed into valuable products by C-O bond-cleaving alkylation, for the first time without the limiting β-hydride elimination. This new nickel-catalyzed dealkoxylative alkylation method enables powerful orthogonal synthetic strategies for the transformation of a variety of naturally occurring and easily accessible anisole derivatives. The directing and/or activating properties of aromatic methoxy groups are utilized first, before they are replaced by alkyl chains in a subsequent coupling process.
Palladium-catalyzed arylation of simple arenes with iodonium salts
Storr, Thomas E.,Greaney, Michael F.
supporting information, p. 1410 - 1413 (2013/05/09)
The development of an arylation protocol for simple arenes with diaryliodonium salts using the Herrmann-Beller palladacycle catalyst is reported. The reaction takes simple aromatic feedstocks and creates valuable biaryls for use in all sectors of the chem
Direct benzylic alkylation via Ni-catalyzed selective benzylic sp 3 C-O activation
Guan, Bing-Tao,Xiang, Shi-Kai,Wang, Bi-Qin,Sun, Zuo-Peng,Wang, Yang,Zhao, Ke-Qing,Shi, Zhang-Jie
, p. 3268 - 3269 (2008/10/09)
This article demonstrates the first cross coupling of benzyl ether with Grignard reagents via Ni-catalyzed benzylic sp3 C-O activation with high efficiency and excellent chemoselectivity. Benzylic sp3 C-O and aryl sp2 C-O were differentiated, controlled by ligands. Copyright
Equilibria of isomeric transformations of alkylbiphenyls
Roshchupkina, I. Yu.,Nesterova, T. N.,Rozhnov, A. M.
, p. 299 - 306 (2007/10/02)
Equilibria of mutual transformations of mono-, di-, and tri-alkylbiphenyls (ABP) were investigated in the liquid phase at 308 to 423 K.On the basis of experimental equilibrium constants, values of ΔrHm0/(kJ * mol-1) and ΔrSm0/(J * K-1 * mol-1) were calculated.Below are given correspondingly: reaction, compound and values for Et-BP (I), i-Pr-BP (II), and t-Bu-BP (III): 4-ABP = 3-ABP, I, 0.23, 5.76; II, (0.45+/-0.4), (5.72+/-1.13); III, (0.48+/-0.53), (4.83+/-0.53); 2-ABP = 4-ABP, I, -3,3, -5.76; II, -12.6, -5.76; III, -15.4, -5.76; 3,5-di-ABP = 3,3'-di-ABP, I, -0.1, 5.76; II, (0+/-0.60), (5.98+/-1.65); III, (-1.34+/-0.67), (4.48+/-1.87); 3,3'-di-ABP = 3,4'-di-ABP, I, -0.37, 0; II, (-0.64+/-1.6), (-0.48+/-4.6); III, (-0.90+/-0.39), (0+/-1.08); 4,4'-di-ABP = 4,3'-di-ABP, I, 0.24, 11.53; II, (0.47+/-0.06), (11.88+/-0.15); III, (0.35+/-2.2), (11.37+/-6.23).The joint processing of the above results gave the values of ΔrHm0/(kJ * mol-1) and ΔrSm0/(J * K-1 * mol-1) for meta-to-para-transformations of ABP: I, 0.33, 0; II, (0.59+/-0.76), (0.31+/-2.12); III, (0.71+/-1.34), (-0.37+/-3.78).
