36266-40-7Relevant academic research and scientific papers
Nickel-Catalyzed Enantioselective Hydroboration of Vinylarenes
Tran, Hai N.,Stanley, Levi M.
supporting information, p. 395 - 399 (2021/12/27)
The enantioselective hydroboration of vinylarenes catalyzed by a chiral, nonracemic nickel catalyst is presented as a facile method for generating chiral benzylic boronate esters. Various vinylarenes react with bis(pinacolato)diboron (B2pin2) in the presence of MeOH as a hydride source to form chiral boronate esters in up to 92% yield with up to 94% ee. The use of anhydrous Me4NF to activate B2pin2 is crucial for ensuring fast transmetalation to achieve high enantioselectivities.
Alkylation of monomeric, dimeric, and polymeric lignin models through carbon-hydrogen activation using Ru-catalyzed Murai reaction
Zuleta, Ernesto C.,Bozell, Joseph J.
, (2021/10/05)
In this study, we have assessed directed carbon-hydrogen activation (CHA) for alkylation of monomeric, dimeric, and polymeric lignin models using Murai's catalyst [RuH2(CO)(PPh3)3]. Based on related work from our laboratory showing that isolated organosolv lignin bears benzylic directing groups ideal for CHA reactions, this approach could offer new methodology for the valorization of biorefinery lignin. Monomeric and dimeric models bearing a keto group at the benzylic position undergo Ru-catalyzed alkylation in good to excellent yield. Similarly, models bearing a benzylic OH group also undergo alkylation via a tandem oxidation/alkylation process enabled by the Ru catalyst. Polymeric models show low levels of functionalization as a result of the poor solubility of the starting polymer. With unsymmetrical models, functionalization occurs first at the least sterically hindered ortho-site, but a subsequent alkylation, leading to disubstituted products can occur at the more sterically hindered site, leading to hexasubstituted arenes. The reaction shows sensitivity to free phenolic OH groups, which appears to reduce the yield in some reactions, and is also a contributing factor to the low yields observed with polymeric lignin models. Combining CHA methodology with lignin isolation technology able to introduce appropriate directing groups for catalytic functionalization will form the basis for improved conversion of lignin to high value chemical products.
Highly efficient Meerwein-Ponndorf-Verley reductions over a robust zirconium-organoboronic acid hybrid
Song, Jinliang,Hua, Manli,Huang, Xin,Visa, Aurelia,Wu, Tianbin,Fan, Honglei,Hou, Minqiang,Zhang, Zhaofu,Han, Buxing
, p. 1259 - 1265 (2021/02/26)
The Meerwein-Ponndorf-Verley (MPV) reaction is an attractive approach to selectively reduce carbonyl groups, and the design of advanced catalysts is the key for these kinds of interesting reactions. Herein, we fabricated a novel zirconium organoborate using 1,4-benzenediboronic acid (BDB) as the precursor for MPV reduction. The prepared Zr-BDB had excellent catalytic performance for the MPV reduction of various biomass-derived carbonyl compounds (i.e., levulinate esters, aldehydes and ketones). More importantly, the number of borate groups on the ligands significantly affected the catalytic activity of the Zr-organic ligand hybrids, owing to the activation role of borate groups on hydroxyl groups in the hydrogen source. Detailed investigations revealed that the excellent performance of Zr-BDB was contributed by the synergetic effect of Zr4+and borate. Notably, this is the first work to enhance the activity of Zr-based catalysts in MPV reactions using borate groups.
Selective Carbon-Carbon Bond Amination with Redox-Active Aminating Reagents: A Direct Approach to Anilines?
Qiu, Xu,Wang, Yachong,Su, Lingyu,Jin, Rui,Song, Song,Qin, Qixue,Li, Junhua,Zong, Baoning,Jiao, Ning
supporting information, p. 3011 - 3016 (2021/09/13)
Amines are among the most fundamental motifs in chemical synthesis, and the introduction of amine building blocks via selective C—C bond cleavage allows the construction of nitrogen compounds from simple hydrocarbons through direct skeleton modification. Herein, we report a novel method for the preparation of anilines from alkylarenes via Schmidt-type rearrangement using redox-active amination reagents, which are easily prepared from hydroxylamine. Primary amines and secondary amines were prepared from corresponding alkylarenes or benzyl alcohols under mild conditions. Good compatibility and valuable applications of the transformation were also displayed.
Dihydropyrimidinones: Efficient one-pot green synthesis using Montmorillonite-KSF and evaluation of their cytotoxic activity
Alharthi, Fahad A.,Alsalme, Ali,Dar, Bashir A.,Farooq, Saleem,Hamid, Abid,Hussain, Aashiq,Koul, S.
, p. 42221 - 42234 (2020/12/09)
A simple, efficient, cost-effective, recyclable and green approach has been developed for the synthesis of new dihydropyrimidinone analogs via the Biginelli reaction. The methodology involves a multicomponent reaction catalyzed by "HPA-Montmorillonite-KSF"as a reusable and heterogeneous catalyst. This method gives an efficient and much improved modification of the original Biginelli reaction, in terms of yield and short reaction times under solvent free conditions. All the derivatives were subjected to cytotoxicity screening against a panel of four different human cancer cell lines viz. colon (Colo-205), prostate (PC-3), leukemia (THP-1) and lung (A549) to check their effect on percentage growth. MTT [3-(4,5-dimethylthiazol-yl)-diphenyl tetrazoliumbromide] cytotoxicity assay was employed to check IC50 values. Of the synthesized analogs, 16a showed the best activity with IC50 of 7.1 ± 0.8, 13.1 ± 1.4, 13.8 ± 0.9 and 14.7 ± 1.1 μM against lung (A549), leukemia (THP-1), prostate (PC-3) and colon (Colo-205) cancer lines, respectively. The 16a analog was further checked for its effect on cancer cell properties through clonogenic (colony formation) and scratch motility (wound healing) assays and thereby was found that it reduced both the colony formation and migratory properties of the lung cancer cell line (A549). Further, molecular docking studies were performed with 16a to show its binding mode. This journal is
Sequential Cleavage of Lignin Systems by Nitrogen Monoxide and Hydrazine
Altmann, Lisa-Marie,Heinrich, Markus R.,Hofmann, Dagmar,Hofmann, Laura Elena,Prusko, Lea
supporting information, (2020/03/27)
The cleavage of representative lignin systems has been achieved in a metal-free two-step sequence first employing nitrogen monoxide for oxidation followed by hydrazine for reductive C?O bond scission. In combining nitrogen monoxide and lignin, the newly developed valorization strategy shows the particular feature of starting from two waste materials, and it further exploits the attractive conditions of a Wolff-Kishner reduction for C?O bond cleavage for the first time. (Figure presented.).
Base-Mediated Meerwein-Ponndorf-Verley Reduction of Aromatic and Heterocyclic Ketones
Boit, Timothy B.,Mehta, Milauni M.,Garg, Neil K.
supporting information, p. 6447 - 6451 (2019/08/20)
An experimental protocol to achieve the Meerwein-Ponndorf-Verley (MPV) reduction of ketones under mildly basic conditions is reported. The transformation is tolerant of a range of ketone substrates, including O- and S-containing heterocycles, is scalable, and shows potential to be used as a platform to access enantioenriched products. These studies provide a general method for achieving the reduction of ketones under mildly basic conditions and offer an alternative protocol to more well-known Al-based MPV reduction conditions.
COMPOSITIONS AND METHODS FOR REDUCTION OF KETONES, ALDEHYDES AND IMINIUMS, AND PRODUCTS PRODUCED THEREBY
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Paragraph 0091-0092, (2018/01/20)
A method of producing an alcohol, comprises reducing an aldehyde or a ketone with a hydridosilatrane. The reducing is carried out with an activator.
1-Hydrosilatrane: A Locomotive for Efficient Ketone Reductions
Varjosaari, Sami E.,Skrypai, Vladislav,Suating, Paolo,Hurley, Joseph J. M.,Gilbert, Thomas M.,Adler, Marc J.
supporting information, p. 229 - 232 (2017/01/24)
An efficient method for the reduction of ketones with 1-hydrosilatrane is described. In the presence of a Lewis base activator, the resulting secondary alcohols are rapidly formed in good to excellent yields (20 examples, 71–99 % yields). The relative bulkiness of 1-hydrosilatrane also enables the diastereoselective reduction of (–)-menthone to (+)-neomenthol, and the use of a chiral alkoxide activator can lead to the enantioselective reduction of prochiral ketones.
Aryl appended neutral and cationic half-sandwich ruthenium(II)-NHC complexes: Synthesis, characterisation and catalytic applications
Viji, Mambattakkara,Tyagi, Nidhi,Naithani, Neeraj,Ramaiah, Danaboyina
, p. 12736 - 12745 (2017/11/06)
Half-sandwich ruthenium(ii) complexes 1-6 bearing imidazolylidene and pyridyl-imidazolylidene ligands have been synthesised in good yields and were characterised on the basis of spectral and analytical evidence. In addition, the structures of the complexes 1-4 were unambiguously established through single crystal X-ray analysis. Transmetalation of the ligands followed by complexation with ruthenium precursors yielded the air and moisture stable complexes. The crystal structures of these complexes exhibited piano-stool geometries with η6-coordination of the p-cymene or hexamethylbenzene moieties. These complexes exhibited catalytic activity in the transfer hydrogenation of carbonyls in an alkaline medium using 2-propanol as the hydrogen source. The effect of variations in the catalyst structure on the transfer hydrogenation and stability was investigated in detail, and theoretical calculations were employed to understand the mechanism of the catalytic activity. The neutral ruthenium-NHC complexes 1 and 2 showed the efficiency of ca. 100% at a catalyst loading of ca. 2 mol% within 2 h of the reaction in 2-propanol, whereas quantitative yields were obtained in the presence of cationic ruthenium-NHC complexes 3-6 within 1 h at a low catalyst loading of ca. 0.5 mol%, thereby demonstrating their robustness for the transfer hydrogenation of the aromatic ketones.
