A study of hydrogenation of benzhydrols in the presence of catalytic amount of triflic acid

2000 ◽  
Vol 78 (9) ◽  
pp. 1242-1246 ◽  
Author(s):  
Christophe Waterlot ◽  
Daniel Couturier ◽  
Marc De Backer ◽  
Benoît Rigo
Keyword(s):  
Catalytic Reduction ◽  
Catalytic Amount ◽  
Ionic Hydrogenation ◽  
Triflic Acid ◽  
Acid Proceeds

The ionic hydrogenation of diarylcarbinols by triethylsilane, in the presence of catalytic amount of triflic acid proceeds via dibenzhydryl ethers. These ethers do not disproportionate to benzophenones and diphenylmethanes but are reduced by triethylsilane to diarylmethanes.Key words: catalytic reduction, benzhydrols, dibenzhydryl ethers, triethylsilane.

A Metal-free Catalytic Reduction of α,β-unsaturated Carbonyl Compounds with Phenyldimethylsilane

2005 ◽  
Vol 2005 (7) ◽  
pp. 469-470 ◽  
Author(s):  
Ruizhu Mu ◽  
Zhengang Liu ◽  
Zhongquan Liu ◽  
Li Yang ◽  
Longmin Wu ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Carbonyl Compounds ◽  
Catalytic Reduction ◽  
Selective Reduction ◽  
Catalytic Amount ◽  
Metal Free

Selective reduction of α,β-unsaturated carbonyl compounds to the corresponding saturated ones by phenyldimethyl silane was promoted by a catalytic amount of I2O5 at ambient temperature in CH2Cl2.

ChemInform Abstract: A Study of Hydrogenation of Benzhydrols in the Presence of Catalytic Amount of Triflic Acid.

ChemInform ◽  
2001 ◽  
Vol 32 (4) ◽  
pp. no-no
Author(s):  
Christophe Waterlot ◽  
Daniel Couturier ◽  
Marc De Backer ◽  
Benoit Rigo
Keyword(s):  
Catalytic Amount ◽  
Triflic Acid

Catalytic reduction of benzoate esters and lactones in the presence of PhMeSiH2 and a titanocene-based catalyst

2002 ◽  
Vol 80 (5) ◽  
pp. 489-495 ◽  
Author(s):  
Ronghua Shu ◽  
John F Harrod ◽  
Anne-Marie Lebuis
Keyword(s):  
Catalytic Reduction ◽  
Catalytic Amount ◽  
Ethyl Benzoate ◽  
Ethoxy Group ◽  
Reaction Conditions ◽  
X Ray ◽  
Stoichiometric Amount ◽  
Stoichiometric Reaction

PhMeSiH2 reduces ethyl benzoate in the presence of a Cp2TiMe2 (Cp = η5-cyclopentadienyl) catalyst to give PhMeSi(OEt)(OCH2Ph) (1). Small to moderate amounts of toluene are also produced, depending on the reaction conditions. Under 40 psi of H2 the same reaction gives quantitative reduction of the ester to toluene. PhCHO is reduced, under the same conditions as the ester, to a mixture of PhMeSi(OCH2Ph)2 and toluene in proportions similar to that observed with the ester. A stoichiometric reaction of PhMeSiH2, PhCOOEt, and Cp2TiMe2 resulted in the formation of known [Cp2Ti(OEt)]2 (2) in 75% isolated yield. A mechanism is proposed in which the C=O of the ester inserts into a Ti–H bond. A Ti-mediated transfer of the ethoxy group from the resulting (α-ethoxy)benzyloxytitanium intermediate to silicon produces PhMeSi(OEt)H and PhCHO. 1 is generated via hydrosilation of PhCHO by PhMeSi(OEt)H. Both β- and γ-butyrolactones react with PhMeSiH2 in the presence of a catalytic amount of Cp2TiMe2 to produce copolymers -[O-PhMeSi-O(CH2)3CHR]n- (R = H, 3; R = Me, 4) (Mw [Formula: see text] 1 × 103; Mw/Mn [Formula: see text] 1.3). A mechanism analogous to that proposed for the ethyl benzoate reduction is proposed. A reaction of PhMeSiH2 and γ-butyrolactone with a stoichiometric amount of Cp2TiMe2 in the presence of tetrahydofuran (THF) produces Cp2Ti(µ-H)(µ-η1,η5-C5H4)Ti(OC4H8)Cp(5) (65% isolated yield) whose structure is determined by X-ray crystallography.Key words: hydrosilation, esters, lactones, titanocene, catalysis.

Highly dispersed MnOx–FeOx supported by silicalite-1 for the selective catalytic reduction of NOx with NH3 at low temperatures

2020 ◽  
Vol 10 (16) ◽  
pp. 5525-5534 ◽  
Author(s):  
Jialiang Gu ◽  
Bingjun Zhu ◽  
Rudi Duan ◽  
Yan Chen ◽  
Shaoxin Wang ◽  
...  
Keyword(s):  
Selective Catalytic Reduction ◽  
Low Temperatures ◽  
Catalytic Reduction ◽  
Highly Dispersed ◽  
Reduction Of Nox

MnOx–FeOx-Loaded silicalite-1 catalysts exhibit high NOx conversion at low temperatures.

Transition-metal-free catalytic hydroboration reduction of amides to amines

2020 ◽  
Vol 7 (21) ◽  
pp. 3515-3520
Author(s):  
Wubing Yao ◽  
Jiali Wang ◽  
Aiguo Zhong ◽  
Shiliang Wang ◽  
Yinlin Shao
Keyword(s):  
Transition Metal ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Value Added ◽  
Metal Free

The selective catalytic reduction of amides to value-added amine products is a desirable but challenging transformation.

Reversing Reactivity: Stereoselective Desulfurative β-O-Glycosylation of Anomeric Thiosugars with Carboxylic Acids Under Copper or Cobalt Catalysis

2019 ◽  
Author(s):  
Samir Messaoudi ◽  
Nedjwa Bennai ◽  
Amelie Chabrier ◽  
Maha Fatthalla ◽  
Expédite Yen-Pon ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
Late Stage ◽  
Catalytic Amount ◽  
Broad Scope ◽  
Wide Range ◽  
Glycosylation Reaction

We have discovered a new mode of reactivity of 1-thiosugars in the presence of Cu(II) or Co(II) for a stereoselective <i>O</i>-glycosylation reaction. The process involves the use of a catalytic amount of Cu(acac)2 or Co(acac)2 and Ag2CO3 as an oxidant in α,α,α-trifluorotoluene (TFT). Moreover, this protocol turned out to have a broad scope, allowing to prepare a wide range of com-plex substituted <i>O</i>-glycoside esters in good to excellent yields with an exclusive β-selectivity. The late-stage modification of phar-maceuticals by this method was also demonstrated.

Photocatalytic Alkylation of Pyrroles and Indoles with α-Diazo Esters

2019 ◽  
Author(s):  
Łukasz Ciszewski ◽  
Jakub Durka ◽  
Dorota Gryko
Keyword(s):  
Aromatic Compounds ◽  
Reaction Pathway ◽  
Alkylating Agents ◽  
Catalytic Amount ◽  
Radical Formation ◽  
Reaction Selectivity ◽  
Diazo Esters ◽  
Electron Withdrawing Substituents

This article describes direct photoalkylation of electron-rich aromatic compounds with diazo compoiunds. C-2 alkylated indoles and pyrroles are obtained with good yields even though the photocatalyst (Ru(bpy)3Cl2) loading is as low as 0.075 mol %. For substrates bearing electron-withdrawing substituents the addition of a catalytic amount of N,N-dimethyl-4-methoxyaniline is required. Both EWG-EWG and EWG-EDG substituted diazo esters are suitable as alkylating agents. The reaction selectivity and mechanistic experiments suggest that carbenes/carbenoid intermediates are not involved in the reaction pathway, instead radical formation is proposed.

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