95280-67-4Relevant academic research and scientific papers
Pd-catalyzed Oxidative Cross-coupling of Alkyl Chromium(0) Fischer Carbene Complexes with Organoboronic Acids
Wang, Kang,Yang, Jinghui,Yao, Xingqi,Wang, Jianbo
, p. 3165 - 3168 (2018)
Alkyl chromium(0) carbene complexes have been explored as the cross-coupling partners in the palladium-catalyzed reaction with aryl or alkenyl boronic acids. This coupling reaction displays the versatile reactivities of alkyl chromium(0) carbenes under palladium catalysis. Mechanistically, this transformation is proposed to involve deprotonation of the alkyl chromium carbene substrate to generate a vinyl chromium anion intermediate that undergoes transmetalation to organopalladium species and reductive elimination.
Scope and Mechanism of the Redox-Active 1,2-Benzoquinone Enabled Ruthenium-Catalyzed Deaminative α-Alkylation of Ketones with Amines
Kirinde Arachchige, Pandula T.,Handunneththige, Suhashini,Talipov, Marat R.,Kalutharage, Nishantha,Yi, Chae S.
, p. 13962 - 13972 (2021/11/20)
The catalytic system formed in situ from the reaction of a cationic Ru-H complex with 3,4,5,6-tetrachloro-1,2-benzoquinone was found to mediate a regioselective deaminative coupling reaction of ketones with amines to form the α-alkylated ketone products. Both benzylic and aliphatic primary amines were found to be suitable substrates for the coupling reaction with ketones in forming the α-alkylated ketone products. The coupling reaction of PhCOCD3 with 4-methoxybenzylamine showed an extensive H/D exchange on both α-CH2 (41% D) and β-CH2 (21%) positions on the alkylation product. The Hammett plot obtained from the reaction of acetophenone with para-substituted benzylamines p-X-C6H4CH2NH2 (X = OMe, Me, H, F, Cl, CF3) showed a strong promotional effect by the amine substrates with electron-releasing groups (ρ = -0.49 ± 0.1). The most significant carbon isotope effect was observed on the α-carbon of the alkylation product (Cα = 1.020) from the coupling reaction of acetophenone with 4-methoxybenzylamine. The kinetics of the alkylation reaction from an isolated imine substrate led to the empirical rate law: rate = k[Ru][imine]. A catalytically active Ru-catecholate complex was synthesized from the reaction of the cationic Ru-H complex with 3,5-di-tert-butyl-1,2-benzoquinone and PCy3. The DFT computational study was performed on the alkylation reaction, which revealed a stepwise mechanism of the [1,3]-carbon migration step via the formation of a Ru(IV)-alkyl species with a moderate energy of activation (ΔG? = 32-42 kcal/mol). A plausible mechanism of the catalytic alkylation reaction via an intramolecular [1,3]-alkyl migration of an Ru-enamine intermediate has been compiled on the basis of these experimental and computational data.
Structural elucidation, bio-inspired synthesis, and biological activities of cyclic diarylpropanes from Horsfieldia kingii
Chen, Lei,Chen, Ye-Gao,Li, Dashan,Liu, Yuan-Lie,Shao, Li-Dong,Wang, Wen-Jing,Xie, Xiao-Yan,Zhan, Rui
supporting information, (2020/09/02)
Bioactivity-guided phytochemical investigation on 70% aqueous acetone extracts of the twigs and leaves of Horsfieldia kingii led to the isolation of two novel cyclic diarylpropanes (1 and 2) bearing a 2,3-dihydro-1H-indene core, one new diarylpropane (3), six known diarylpropanes (4–9), one flavanol (10), and seven lignans (11–17). Their structures were determined by extensive spectroscopic analysis, electronic circular dichroism calculations, and X-ray diffraction crystallography. Moreover, a biomimetic synthesis of 1 and 2 were accomplished in four steps. The in vitro nitric oxide production inhibition tests of these compounds revealed that compounds (±)-2, (+)-2, (?)-2, and 10 were potential with IC50 values lower than 10 μM. Compound 2 could inhibit iNOS expression in LPS-induced RAW264.7 cells at a series of non-cytotoxic concentrations (20 μM). Furthermore, the bioassay results also suggested the primary SARs of 1-phenyl-2,3-dihydro-1H-indene based scaffold.
Utility of Organoboron Reagents in Arylation of Cyclopropanols via Chelated Pd(II) Catalysis: Chemoselective Access to β-Aryl Ketones
Ilangovan, Andivelu,Ramar, Thangeswaran,Subbaiah, Murugaiah A. M.
, (2020/07/03)
Organoborane reagents were investigated as coupling partners to cyclopropanol-derived β-ketone enolates in the presence of a chelated Pd(II) catalyst. Efficient coupling of a range of electronically and sterically diverse cyclopropanols and aryl/alkenyl boronic derivatives (39 examples, 65-94% yield) could be achieved with the generation of synthetically important β-aryl ketone intermediates in a chemoselective fashion. This reactivity paradigm, which broadens the scope of aryl donor partners to homoenolates, allows open-flask conditions, water as a cosolvent, and preparation of halogen-bearing β-aryl ketones that are distinct from previous methods. This chelated Pd(II) catalysis appears to be different from the Pd(0) pathway, as evident from deuterium scrambling studies that could reveal differentiating protonolysis of an α-keto carbopalladium complex in the terminal step.
Synthesis and Structures of Arene Ruthenium (II)–NHC Complexes: Efficient Catalytic α-alkylation of ketones via Hydrogen Auto Transfer Reaction
Balamurugan, Gunasekaran,Balaji, Sundarraman,Ramesh, Rengan,Bhuvanesh, Nattamai S.P.
, (2018/11/25)
A panel of six new arene Ru (II)-NHC complexes 2a-f, (NHC?=?1,3-diethyl-(5,6-dimethyl)benzimidazolin-2-ylidene 1a, 1,3-dicyclohexylmethyl-(5,6-dimethyl)benzimidazolin-2-ylidene 1b and 1,3-dibenzyl-(5,6-dimethyl)benzimidazolin-2-ylidene 1c) were synthesized from the transmetallation reaction of Ag-NHC with [(η6-arene)RuCl2]2 and characterized. The ruthenium (II)-NHC complexes 2a-f were developed as effective catalysts for α-alkylation of ketones and synthesis of bioactive quinoline using primary/amino alcohols as coupling partners respectively. The reactions were performed with 0.5?mol% catalyst load in 8?h under aerobic condition and the maximum yield was up to 96%. Besides, the different alkyl wingtips on NHC and arene moieties were studied to differentiate the catalytic robustness of the complexes in the transformations.
Alkylation of Ketones Catalyzed by Bifunctional Iron Complexes: From Mechanistic Understanding to Application
Seck, Charlotte,Mbaye, Mbaye Diagne,Coufourier, Sébastien,Lator, Alexis,Lohier, Jean-Fran?ois,Poater, Albert,Ward, Thomas R.,Gaillard, Sylvain,Renaud, Jean-Luc
, p. 4410 - 4416 (2017/11/20)
Cyclopentadienone iron dicarbonyl complexes were applied in the alkylation of ketones with various aliphatic and aromatic ketones and alcohols via the borrowing hydrogen strategy in mild reaction conditions. DFT calculations and experimental works highlight the role of the transition metal Lewis pairs and the base. These iron complexes demonstrated a broad applicability in mild conditions and extended the scope of substrates.
