scholarly journals Cu-catalyzed trifluoromethylation of aryl iodides with trifluoromethylzinc reagent prepared in situ from trifluoromethyl iodide

2013 ◽  
Vol 9 ◽  
pp. 2404-2409 ◽  
Author(s):  
Yuzo Nakamura ◽  
Motohiro Fujiu ◽  
Tatsuya Murase ◽  
Yoshimitsu Itoh ◽  
Hiroki Serizawa ◽  
...  
Keyword(s):  
Copper Salt ◽  
Catalytic Reactions ◽  
Metal Fluoride ◽  
Reaction Conditions ◽  
Aryl Iodides ◽  
Silyl Groups ◽  
High Yields

The trifluoromethylation of aryl iodides catalyzed by copper(I) salt with trifluoromethylzinc reagent prepared in situ from trifluoromethyl iodide and Zn dust was accomplished. The catalytic reactions proceeded under mild reaction conditions, providing the corresponding aromatic trifluoromethylated products in moderate to high yields. The advantage of this method is that additives such as metal fluoride (MF), which are indispensable to activate silyl groups for transmetallation in the corresponding reactions catalyzed by copper salt by using the Ruppert–Prakash reagents (CF3SiR3), are not required.

In situ loading of well-dispersed silver nanoparticles on nanocrystalline magnesium oxide for real-time monitoring of catalytic reactions by surface enhanced Raman spectroscopy

Nanoscale ◽  
2015 ◽  
Vol 7 (40) ◽  
pp. 16952-16959 ◽  
Author(s):  
Kaige Zhang ◽  
Gongke Li ◽  
Yuling Hu
Keyword(s):  
Raman Spectroscopy ◽  
Surface Enhanced Raman Spectroscopy ◽  
Catalytic Reactions ◽  
Reaction Intermediates ◽  
Reaction Conditions ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Nanocrystalline Magnesium Oxide ◽  
Insight Into

The surface-enhanced Raman spectroscopy (SERS) technique is of great importance for insight into the transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions under actual reaction conditions, especially in water.

57Fe Mössbauer Spectroscopic Study of the Geometrical Effects In the Catalytic Reactions with Intercalation Compounds

1982 ◽  
Vol 20 ◽  
Author(s):  
P.P. Vaishnava ◽  
P.A. Montano
Keyword(s):  
Ferric Chloride ◽  
Catalytic Reactions ◽  
Fischer Tropsch ◽  
Reaction Conditions ◽  
Intercalated Graphite ◽  
The Third ◽  
Intercalated Compounds ◽  
Catalytic Sites ◽  
Geometrical Effects

ABSTRACTIn situ 57Fe Mössbauer spectra are reported for the first-, higher-stage ferric chloride, and a mixed ferric chloride-potassium chloride intercalated graphite catalysts under reduction and Fischer-Tropsch reaction conditions. The mass spectroscopic measurements reveal a different catalytic selectivity for the three catalysts. The first two catalysts predominantly possess a higher selectivity for methane, whereas the third catalyst has higher selectivity for the formation of propane. The differences are attributed to geometrical effects in the catalytic sites of the intercalated compounds.

Radical Metal-Free Borylation of Aryl Iodides

Synthesis ◽  
2017 ◽  
Vol 49 (21) ◽  
pp. 4759-4768 ◽  
Author(s):  
Sandra Pinet ◽  
Mathieu Pucheault ◽  
Virginie Liautard ◽  
Mégane Debiais
Keyword(s):  
Steric Hindrance ◽  
Radical Mechanism ◽  
Electronic Effects ◽  
Simple Metal ◽  
Reaction Conditions ◽  
Metal Free ◽  
Aryl Iodides ◽  
Reaction Proceeds ◽  
Electronic Effects Of Substituents

A simple metal-free borylation of aryl iodides mediated by a fluoride sp2–sp3 diboron adduct is described. The reaction conditions are compatible with various functional groups. Electronic effects of substituents do not affect the borylation while steric hindrance does. The reaction proceeds via a radical mechanism in which pyridine serves to stabilize the boryl radicals, generated in situ.

scholarly journals One-Step Synthesis of Acylboron Compounds via Cu-Catalyzed Carbonylative Borylation of Alkyl Halides

2020 ◽  
Author(s):  
Cheng Li-Jie ◽  
Zhao Siling ◽  
Neal Mankad
Keyword(s):  
Alkyl Halides ◽  
Efficient Synthesis ◽  
Mechanistic Studies ◽  
Acyl Halide ◽  
Reaction Conditions ◽  
One Pot ◽  
One Step ◽  
High Yields ◽  
Tertiary Alkyl

A Cu-catalyzed carbonylative borylation of unactivated alkyl halides has been developed, enabling efficient synthesis of aliphatic potassium acyltrifluoroborates (KATs) in high yields by treating the in-situ formed tetracoordinated acylboron intermediates with aqueous KHF2. A variety of functional groups are tolerated under the mild reaction conditions, and primary, secondary and tertiary alkyl halides are all applicable. In addition, this method also provides facile access to N-methyliminodiacetyl (MIDA) acylboronates as well as α-methylated potassium acyltrifluoroborates in a one-pot manner. Mechanistic studies indicate a radical atom transfer carbonylation (ATC) mechanism to form acyl halide intermediates that are subsequently borylated by (NHC)CuBpin.<br>

scholarly journals Gold(I)-catalyzed intramolecular cyclization/intermolecular cycloaddition cascade as a fast track to polycarbocycles and mechanistic insights

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Cheng Zhang ◽  
Kemiao Hong ◽  
Chao Pei ◽  
Su Zhou ◽  
Wenhao Hu ◽  
...  
Keyword(s):  
Fast Track ◽  
Cycloaddition Reaction ◽  
Structural Diversity ◽  
Mechanistic Studies ◽  
Reaction Conditions ◽  
In Situ Formation ◽  
Increasing Demand ◽  
High Yields ◽  
Synthetic Intermediate

AbstractMetal carbene is an active synthetic intermediate, which has shown versatile applications in synthetic chemistry. Although a variety of catalytic methods have been disclosed for the generation of carbene species from different precursors, there is an increasing demand for the development of efficient and practical approaches for the in-situ formation of metal carbene intermediates with structural diversity and unrevealed reactivity. Herein we report a gold-catalyzed cascade protocol for the assembly of polycarbocyclic frameworks in high yields under mild reaction conditions. Mechanistic studies indicate that the unique β-aryl gold-carbene species, generated via gold-promoted 6-endo-dig diazo-yne cyclization, is the key intermediate in this reaction, followed by a [4 + 2]-cycloaddition with external alkenes. In comparison to the well-documented metal carbene cycloadditions, this carbene intermediate serves as a 4-C synthon in a cycloaddition reaction. A variety of elusive π-conjugated polycyclic hydrocarbons (CPHs) with multiple substituents are readily accessible from the initially generated products by a mild oxidation procedure.

scholarly journals Primary Phosphines and Phosphine Oxides with a Stereogenic Carbon Center Adjacent to the Phosphorus Atom: Synthesis and Anti-Markovnikov Radical Addition to Alkenes

Organics ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 395-403
Author(s):  
Toshiaki Murai ◽  
Ryota Wada ◽  
Kouji Iwata ◽  
Yuuki Maekawa ◽  
Kazuma Kuwabara ◽  
...  
Keyword(s):  
Carbon Atom ◽  
Phosphorus Atom ◽  
Organophosphorus Compounds ◽  
Radical Addition ◽  
Secondary Phosphine ◽  
Phosphine Oxides ◽  
Reaction Conditions ◽  
High Yields ◽  
Oxidized Products

Organophosphorus compounds with stereogenic phosphorus and carbon atoms have received increasing attention. In this regards, primary phosphines with a stereogenic carbon atom adjacent to the phosphorus atom were synthesized by the reduction in phosphonates and phosphonoselenoates with a binaphthyl group. Their oxidized products, i.e., phosphine oxides with a stereogenic tetrasubstituted carbon atom, were found to undergo BEt3-mediated radical addition to cyclohexene to give P-stereogenic secondary phosphine oxides with a diastereoselectivity of 91:9. The products were characterized by ordinary analytical methods, such as Fourier transform infrared spectroscopy; 1H, 13C, and 31P NMR spectroscopies; and mass spectroscopy. Computational studies on the phosphorus-centered radical species and the obtained product implied that the thermodynamically stable radical and the adduct may be formed as a major diastereomer. The radical addition to a range of alkenes took place in an anti-Markovnikov fashion to give P-stereogenic secondary phosphine oxides. A variety of functional groups in the alkenes were tolerated under the reaction conditions to afford secondary phosphine oxides in moderate yields. Primary phosphines with an alkenyl group, which were generated in situ, underwent intramolecular cyclization to give five- and six-membered cyclic phosphines in high yields after protection by BH3.

scholarly journals Asymmetric Henry Reaction of Nitromethane with Substituted Aldehydes Catalyzed by Novel In Situ Generated Chiral Bis(β-Amino Alcohol-Cu(OAc)2·H2O Complex

Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1208
Author(s):  
Abdullah Saleh Alammari ◽  
Abdullah Mohammed Al-Majid ◽  
Assem Barakat ◽  
Saeed Alshahrani ◽  
Mohammad Ali ◽  
...  
Keyword(s):  
Amino Alcohol ◽  
Aromatic Aldehydes ◽  
Catalyst System ◽  
Green Solvent ◽  
Henry Reaction ◽  
Key Factors ◽  
Reaction Conditions ◽  
Catalyst Complex ◽  
High Yields

Novel chiral thiophene-2,5-bis(β-amino alcohol) ligands (L1–L5) were designed and synthesized from thiophene-2,5-dicarbaldehyde (3) with chiral β-amino alcohols (4a–e) in 4 steps with overall 23% yields. An in situ generated L-Cu(OAc)2·H2O catalyst system was found to be highly capable catalyst for the asymmetric Henry reaction of nitromethane (7) with various substituted aromatic aldehydes (6a–m) producing chiral nitroaldols product (8a–m) with excellent enantiomeric purity (up to 94.6% ee) and up to >99% chemical yields. 20 mol% of L4-Cu(OAc)2 catalyst complex in EtOH was effective for the asymmetric Henry transformation in 24 h, at ambient temperature. Ease of ligand synthesis, use of green solvent, base free reaction, mild reaction conditions, high yields and excellent enantioselectivity are all key factors that make this catalytic system robust and highly desirable for the access of versatile building block β-nitro alcohol in practical catalytic usage via asymmetric Henry reaction.

scholarly journals One-Step Synthesis of Acylboron Compounds via Cu-Catalyzed Carbonylative Borylation of Alkyl Halides

2020 ◽  
Author(s):  
Cheng Li-Jie ◽  
Zhao Siling ◽  
Neal Mankad
Keyword(s):  
Alkyl Halides ◽  
Efficient Synthesis ◽  
Mechanistic Studies ◽  
Acyl Halide ◽  
Reaction Conditions ◽  
One Pot ◽  
One Step ◽  
High Yields ◽  
Tertiary Alkyl

A Cu-catalyzed carbonylative borylation of unactivated alkyl halides has been developed, enabling efficient synthesis of aliphatic potassium acyltrifluoroborates (KATs) in high yields by treating the in-situ formed tetracoordinated acylboron intermediates with aqueous KHF2. A variety of functional groups are tolerated under the mild reaction conditions, and primary, secondary and tertiary alkyl halides are all applicable. In addition, this method also provides facile access to N-methyliminodiacetyl (MIDA) acylboronates as well as α-methylated potassium acyltrifluoroborates in a one-pot manner. Mechanistic studies indicate a radical atom transfer carbonylation (ATC) mechanism to form acyl halide intermediates that are subsequently borylated by (NHC)CuBpin.<br>

Novel One-pot Synthesis of Pyranocarbazole Derivatives via an Isocyanide-based Three-component Reaction

2020 ◽  
Vol 17 ◽  
Author(s):  
Visarapu Malathi ◽  
Pedavenkatagari Narayana Reddy ◽  
Pannala Padmaja
Keyword(s):  
Efficient Method ◽  
Atom Economy ◽  
Reaction Conditions ◽  
One Pot ◽  
Catalyst Free ◽  
One Pot Synthesis ◽  
Three Component Reaction ◽  
High Yields

Abstract:: An efficient method has been developed for the synthesis of new pyrano[3,2-c] and pyrano[3,2-a]carbazole de-rivatives via a three component reaction of 4-hydroxycarbazole or 2-hydroxycarbazole, isocyanides, and dialkylacetylenedi-carboxylates. Noteworthy features of this protocol include mild reaction conditions, catalyst-free, high atom-economy and high yields.

The electron-transfer intermediates of the oxygen evolution reaction (OER) as polarons by in situ spectroscopy

2021 ◽  
Author(s):  
Hanna Lyle ◽  
Suryansh Singh ◽  
Michael Paolino ◽  
Ilya Vinogradov ◽  
Tanja Cuk
Keyword(s):  
Electron Transfer ◽  
Oxygen Evolution ◽  
Oxygen Evolution Reaction ◽  
Catalytic Reactions ◽  
In Situ Spectroscopy ◽  
Chemical Bonds

The conversion of diffusive forms of energy (electrical and light) into short, compact chemical bonds by catalytic reactions regularly involves moving a carrier from an environment that favors delocalization to one that favors localization.

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