6965-78-2Relevant articles and documents
Experimental and Computational Studies on the Ruthenium-Catalyzed Dehydrative C-H Coupling of Phenols with Aldehydes for the Synthesis of 2-Alkylphenol, Benzofuran, and Xanthene Derivatives
Baik, Mu-Hyun,Pannilawithana, Nuwan,Pudasaini, Bimal,Yi, Chae S.
supporting information, p. 13428 - 13440 (2021/09/07)
The cationic Ru-H complex [(C6H6)(PCy3)(CO)RuH]+BF4- (1) was found to be an effective catalyst for the dehydrative C-H coupling reaction of phenols and aldehydes to form 2-alkylphenol products. The coupling reaction of phenols with branched aldehydes selectively formed 1,1-disubstituted benzofurans, while the coupling reaction with salicylaldehydes yielded xanthene derivatives. A normal deuterium isotope effect was observed from the coupling reaction of 3-methoxyphenol with benzaldehyde and 2-propanol/2-propanol-d8 (kH/kD = 2.3 ± 0.3). The carbon isotope effect was observed on the benzylic carbon of the alkylation product from the coupling reaction of 3-methoxyphenol with 4-methoxybenzaldehyde (C(3) 1.021(3)) and on both benzylic and ortho-arene carbons from the coupling reaction with 4-trifluorobenzaldehdye (C(2) 1.017(3), C(3) 1.011(2)). The Hammett plot from the coupling reaction of 3-methoxyphenol with para-substituted benzaldehydes p-X-C6H4CHO (X = OMe, Me, H, F, Cl, CF3) displayed a V-shaped linear slope. Catalytically relevant Ru-H complexes were observed by NMR from a stoichiometric reaction mixture of 1, 3-methoxyphenol, benzaldehyde, and 2-propanol in CD2Cl2. The DFT calculations provided a detailed catalysis mechanism featuring an electrophilic aromatic substitution of the aldehyde followed by the hydrogenolysis of the hydroxy group. The calculations also revealed a mechanistic rationale for the strong electronic effect of the benzaldehdye substrates p-X-C6H4CHO (X = OMe, CF3) in controlling the turnover-limiting step. The catalytic C-H coupling method provides an efficient synthetic protocol for 2-alkylphenols, 1,1-disubstituted benzofurans, and xanthene derivatives without employing any reactive reagents or forming wasteful byproducts.
Synthesis of 2-acylphenol and flavene derivatives from the ruthenium-catalyzed oxidative c-h acylation of phenols with aldehydes
Lee, Hanbin,Yi, Chae S.
, p. 1899 - 1904 (2015/03/18)
The cationic ruthenium hydride complex [(C6H6)(PCy3)(CO)RuH]+BF4- has been found to be an effective catalyst for the oxidative C-H coupling reaction of phenols with aldehydes to give 2-acylphenol compounds. The coupling of phenols with α,β-unsaturated aldehydes selectively gives the flavene derivatives. The catalytic method mediates direct oxidative C-H coupling of phenol and aldehyde substrates without using any metal oxidants or forming wasteful byproducts. A cationic ruthenium hydride complex catalyzes the oxidative C-H coupling of phenols with aldehydes to form 2-acylphenol and flavene derivatives.
Sodium Borohydride Induced Deamination of Diarylimines
Sharma, Indra,Ray, Suprabhat
, p. 59 - 61 (2007/10/02)
Sodium borohydride reduction of diarylimines (I) in ethanol at room temperature affords the corresponding diarylamines (II) and/or diarylmethanes (III) depending on the nature of substituent in the diaryl moiety of the imines. o-Hydroxydiarylimines, beari
