292825-75-3Relevant academic research and scientific papers
Attenuation of London Dispersion in Dichloromethane Solutions
Pollice, Robert,Bot, Marek,Kobylianskii, Ilia J.,Shenderovich, Ilya,Chen, Peter
supporting information, p. 13126 - 13140 (2017/09/26)
London dispersion constitutes one of the fundamental interaction forces between atoms and between molecules. While modern computational methods have been developed to describe the strength of dispersive interactions in the gas phase properly, the importance of inter-and intramolecular dispersion in solution remains yet to be fully understood because experimental data are still sparse in that regard. We herein report a detailed experimental and computational study of the contribution of London dispersion to the bond dissociation of proton-bound dimers, both in the gas phase and in dichloromethane solution, showing that attenuation of inter-and intramolecular dispersive interaction by solvent is large (about 70% in dichloromethane), but not complete, and that current state-of-The-Art implicit solvent models employed in quantum-mechanical computational studies treat London dispersion poorly, at least for this model system.
Benzoyl peroxide promoted radical ortho-alkylation of nitrogen heteroaromatics with simple alkanes and alcohols
Fang, Lei,Chen, Liangshun,Yu, Jianjun,Wang, Limin
, p. 1910 - 1914 (2015/03/18)
A catalytic amount of benzoyl peroxide (BPO)-initiated cross-dehydrogenative coupling reaction of N-iminopyridine ylides with simple alkanes and alcohols leads to the corresponding 2-alkylpyridines with high regioselectivity in moderate to good yields without an additional reduction step to remove the activated group. A catalytic amount of benzoyl peroxide (BPO)-initiated cross-dehydrogenative coupling reaction of N-iminopyridine ylides with simple alkanes and alcohols has been developed. The strategy allowed convenient access to various 2-alkylpyridines in moderate to good yields without an additional reduction step to remove the activated group.
Metal-Free Oxidative Decarbonylative Coupling of Aliphatic Aldehydes with Azaarenes: Successful Minisci-Type Alkylation of Various Heterocycles
Tang, Ren-Jin,Kang, Lei,Yang, Luo
supporting information, p. 2055 - 2060 (2015/06/23)
A metal-free oxidative decarbonylative coupling of aliphatic aldehydes with various electron-deficient heterocycles has been developed. This reaction is supposed to be realized via a Minisci-type mechanism, based on the substrate scope, regioselectivity and radical trapping experiments. The ready availability of aliphatic aldehydes, metal-free conditions and broad substrate scope should make this method attractive for the late-stage alkylation of bioactive heterocycles.
Palladium-catalyzed intermolecular decarboxylative coupling of 2-phenylbenzoic acids with alkynes via C-H and C-C bond activation
Wang, Congyang,Rakshit, Souvik,Glorius, Frank
supporting information; experimental part, p. 14006 - 14008 (2010/12/24)
A novel protocol for palladium-catalyzed intermolecular formal [4 + 2] annulation of 2-phenylbenzoic acids with alkynes is described. Acridine is shown to be essential for the high reaction efficiency. Phenanthrene derivatives are formed in moderate to good yields without coupling (pseudo)halides or organometallic species.
The AZARYPHOS family of ligands for ambifunctional catalysis: Syntheses and use in ruthenium-catalyzed anti-markovnikov hydration of terminal alkynes
Hintermann, Lukas,Dang, Tuan Thanh,Labonne, Aurelie.,Kribber, Thomas,Xiao, Li,Naumov, Pance
supporting information; experimental part, p. 7167 - 7179 (2010/02/28)
The family of AZARYPHOS (aza-aryl-phosphane) phosphane ligands, containing a phosphine unit and sterically shielded nitrogen lone pairs in the ligand periphery, is introduced as a tool for developing ambifunctional catalysis by the metal center and nitrogen lone pairs in the ligand sphere. General synthetic strategies have been developed to synthesize over 25 examples of structurally diverse (6-aryl-2pyridyl)phosphanes (ARPYPHOS), (6alkyl-2-pyridyl)phosphanes (ALPY-PHOS), 4,6-disubsituted l,3-diazin-2ylphosphanes or l,3,5-triazin-2- ylphosphanes, quinazolinylphosphanes, quinolinylphosphanes, and others. The scalable syntheses proceed in a few steps. The incorporation of AZARYPHOS ligands (L) into complexes [RuCp(L)2(MeCN)][PF6] (Cp = cyclopentadieny1)gives catalysts for the anti-Markovnikov hydration of terminal alkynes of the highest known activities. Electronic and steric ligand effects modulate the reaction kinetics over a range of two orders of magnitude. These results highlight the importance of using structurally diverse ligand families in the process of developing cooperative ambifunctional catalysis by a metal and its ligand.
Mechanistic Evaluation of the Halocyclization of 4-Penten-1-ol by Some Bis(2-substituted pyridine) and Bis(2,6-disubstituted pyridine)bromonium Triflates
Cui, Xi-Lin,Brown
, p. 5653 - 5658 (2007/10/03)
The halocyclization reaction of 4-penten-1-ol mediated by various bis(2-substituted pyridine) and (2,6- disubstituted pyridine)bromonium triflates (P2Br+OTf-) was investigated to determine the influence of the substituents on the mechanism of reaction. In all cases, the reaction proceeds via a two-step process where the starting P2Br+ reversibly dissociates to a reactive monosubstituted PBr+, which then is captured by 4-penten-1-ol to form halocyclized product (2-bromomethyltet-rahydrofuran). The dissociation rate constant of P2Br+ (kd) is sensitive to the steric bulk at the 2- and 6-positions, and in the case of the 2,6-dicyclohexylpyridine or 2,6-dicyclopentylpyridine, the P2Br+ species are too unstable to isolate. The partitioning ratio of the reactive intermediate (PBr+) between reversal and product formation (k-d/k2) is not particularly sensitive to the nature of the pyridine, the limiting values being 3-7 except in the case of bis(2(-)-menthylpyridine)bromonium triflate where the k-d/k2 ratio is ～80. The reaction of 4-penten-1-ol and its OD isotopomer with bis(lutidine)bromonium triflate was investigated to determine the deuterium kinetic isotope effect (dkie) on the bromocyclization reaction. The (k-d/k2)H/D ratio is 1.0, indicating that the rate-limiting step for the bromocyclization is probably formation of a PBr+-4-penten-1-ol complex which does not involve substantial changes in the bonding of the OH. The cyclization of 4-penten-1-ol and 4-pentenoic acid mediated by bis(2(-)-menthylpyridine)bromonium triflate produces an enantiomeric excess in the cyclized products of only 2.4% and 4.8% respectively.
