In situ activation of benzyl alcohols with XtalFluor-E: formation of 1,1-diarylmethanes and 1,1,1-triarylmethanes through Friedel–Crafts benzylation

2015 ◽  
Vol 13 (8) ◽  
pp. 2243-2246 ◽  
Author(s):  
Justine Desroches ◽  
Pier Alexandre Champagne ◽  
Yasmine Benhassine ◽  
Jean-François Paquin
Keyword(s):  
Transition Metal ◽  
Lewis Acid ◽  
Benzyl Alcohols ◽  
Mild Conditions ◽  
In Situ Activation ◽  
Wide Range ◽  
Strong Lewis Acid

The Friedel–Crafts benzylation of arenes using benzyl alcohols activated in situ with XtalFluor-E is described. A wide range of 1,1-diarylmethanes and 1,1,1-triarylmethanes were prepared under simple and mild conditions, without the need for a transition metal or a strong Lewis acid.

Recent Developments in Transition-Metal-Free Functionalization and Derivatization Reactions of Pyridines

Synlett ◽  
2020 ◽  
Author(s):  
Lei Jiao ◽  
Fei-Yu Zhou
Keyword(s):  
Transition Metal ◽  
Structural Motif ◽  
Metal Exchange ◽  
Coupling Reactions ◽  
Phosphonium Salts ◽  
Metal Free ◽  
Radical Coupling ◽  
In Situ Activation ◽  
Recent Developments

AbstractPyridine is an important structural motif that is prevalent in natural products, drugs, and materials. Methods that functionalize and derivatize pyridines have gained significant attention. Recently, a large number of transition-metal-free reactions have been developed. In this review, we provide a brief summary of recent advances in transition-metal-free functionalization and derivatization reactions of pyridines, categorized according to their reaction modes.1 Introduction2 Metalated Pyridines as Nucleophiles2.1 Deprotonation2.2 Halogen–Metal exchange3 Activated Pyridines as Electrophiles3.1 Asymmetric 2-Allylation by Chiral Phosphite Catalysis3.2 Activation of Pyridines by a Bifunctional Activating Group3.3 Alkylation of Pyridines by 1,2-Migration3.4 Alkylation of Pyridines by [3+2] Addition3.5 Pyridine Derivatization by Catalytic In Situ Activation Strategies3.6 Reactions via Heterocyclic Phosphonium Salts4 Radical Reactions for Pyridine Functionalization4.1 Pyridine Functionalization through Radical Addition Reactions4.2 Pyridine Functionalization through Radical–Radical Coupling Reactions5 Derivatization of Pyridines through the Formation of Meisenheimer-Type Pyridyl Anions6 Conclusion

CO2as a hydrogen vector – transition metal diamine catalysts for selective HCOOH dehydrogenation

2017 ◽  
Vol 46 (5) ◽  
pp. 1670-1676 ◽  
Author(s):  
Cornel Fink ◽  
Gábor Laurenczy
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Production ◽  
Transition Metal ◽  
Formic Acid ◽  
Catalytic Dehydrogenation ◽  
Mild Conditions ◽  
Adjustable Rate

The homogeneous catalytic dehydrogenation of formic acid in aqueous solution provides an efficientin situmethod for hydrogen production, under mild conditions, and at an adjustable rate.

[bmim]PF6/KOH: A Recyclable Catalytic System for an Azide–Arylacetaldehyde [3 + 2] Cycloaddition

2017 ◽  
Vol 41 (11) ◽  
pp. 631-635
Author(s):  
Yuqin Jiang ◽  
Kai Wu ◽  
Xuxia Tan ◽  
Dandan Zhang ◽  
Wenpei Dong ◽  
...  
Keyword(s):  
Transition Metal ◽  
Organic Solvent ◽  
Catalytic System ◽  
Room Temperature ◽  
Reaction Medium ◽  
Metal Catalyst ◽  
Transition Metal Catalyst ◽  
Green Protocol ◽  
Mild Conditions

A fast and green protocol for the synthesis of 1,4-disubstituted 1,2,3-triazoles from azides and arylacetaldehydes at room temperature was developed using [bmim]PF6/KOH as the reaction medium. It was found that the in situ-generated carbene from [bmim]PF6/KOH acted as the catalyst. In the absence of a transition-metal catalyst and organic solvent, this azide–arylacetaldehyde [3 + 2] cycloaddition proceeds efficiently, with high levels of regioselectivity, broad range of substrates, excellent yields and simple operation under mild conditions.

Transition Metal-Free Synthesis of Pinacol Arylboronate: Regioselective Boronation of 1,3-Disubstituted Benzenes

2014 ◽  
Vol 67 (4) ◽  
pp. 675 ◽  
Author(s):  
Yan Wang ◽  
Le Wang ◽  
Ling-Yan Chen ◽  
Pinaki S. Bhadury ◽  
Zhihua Sun
Keyword(s):  
Transition Metal ◽  
Regioselective Synthesis ◽  
Ortho Position ◽  
Metal Free ◽  
Disubstituted Benzene ◽  
Wide Range

The regioselective synthesis of pinacol arylboronate has been achieved from 1,3-disubstituted benzene through directed ortho-metallation (DoM)–borylation sequence. A wide range of substituents and borylating reagents were investigated. In situ lithiation and subsequent boronation predominantly occurred at the ortho-position to afford the desired products in moderate yields.

s-Tetrazine: robust and green photo-organocatalyst for aerobic oxidation of N,N-disubstituted-hydroxylamines to nitrones

Synlett ◽  
2021 ◽  
Author(s):  
Jiyuan LYU ◽  
Tuan Le ◽  
Clémence Allain ◽  
Pierre Audebert ◽  
Geraldine Masson
Keyword(s):  
Oxidative Dehydrogenation ◽  
Aerobic Oxidation ◽  
Dehydrogenation Reaction ◽  
Mild Conditions ◽  
Wide Range ◽  
High Yields ◽  
Oxyallyl Cation

Efficient photocatalytic aerobic oxidative dehydrogenation reaction of N,N-disubstituted hydroxylamines to nitrones were developed with an in situ generated photocatalyst based on commercially available 3,6-dichlorotetrazine. This process affords a wide range of nitrones in high yields under mild conditions. In addition, an oxidative (3+3) cycloaddition between an oxyallyl cation precursor and a hydroxylamine was also developed.

scholarly journals Increasing the Brønsted acidity of Ph2PO2H by the Lewis acid B(C6F5)3. Formation of an eight-membered boraphosphinate ring [Ph2POB(C6F5)2O]2

2016 ◽  
Vol 52 (73) ◽  
pp. 10992-10995 ◽  
Author(s):  
Ralf Kather ◽  
Elena Rychagova ◽  
Paula Sanz Camacho ◽  
Sharon E. Ashbrook ◽  
J. Derek Woollins ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Strong Acid ◽  
Bronsted Acid ◽  
Brønsted Acid ◽  
Brønsted Acidity ◽  
Acid Ph ◽  
Brönsted Acidity ◽  
Brönsted Acid ◽  
Strong Lewis Acid

The strong acid (C6F5)3BOPPh2OH, was prepared in situ by the reaction of the rather weak Brønsted acid Ph2PO2H with the strong Lewis acid B(C6F5)3.

Coupling of N-Nosylhydrazones with Nitrosoarenes: Transition-Metal-Free Approach to (Z)-N-Arylnitrones

Synthesis ◽  
2018 ◽  
Vol 50 (08) ◽  
pp. 1728-1736 ◽  
Author(s):  
Tingting Liu ◽  
Zhaohong Liu ◽  
Zhenhua Liu ◽  
Donghua Hu ◽  
Yeming Wang
Keyword(s):  
Transition Metal ◽  
Functional Groups ◽  
Direct Coupling ◽  
Recrystallization Process ◽  
Metal Free ◽  
Mild Conditions ◽  
Wide Range

An efficient and transition-metal-free protocol for the synthesis of (Z)-N-arylnitrones from the direct coupling of N-nosylhydrazones with nitrosoarenes under mild conditions is described. The protocol is compatible with a wide range of functional groups placed on both the reagents and provided the corresponding nitrones in good to excellent yields by simple recrystallization process. The use of these 1,3-dipoles for the synthesis of substituted indoles is elaborated for 2,3-diphenyl-1H-indole.

scholarly journals Phase-segregated NiPx@FePyOz core@shell nanoparticles: ready-to-use nanocatalysts for electro- and photo-catalytic water oxidation through in situ activation by structural transformation and spontaneous ligand removal

2018 ◽  
Vol 9 (21) ◽  
pp. 4830-4836 ◽  
Author(s):  
Masaki Saruyama ◽  
Sunwon Kim ◽  
Toshio Nishino ◽  
Masanori Sakamoto ◽  
Mitsutaka Haruta ◽  
...  
Keyword(s):  
Transition Metal ◽  
Water Oxidation ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Metal Phosphide ◽  
In Situ Activation ◽  
Active Transition ◽  
Transition Metal Phosphide ◽  
Core Shell Nanoparticles

The phase-segregated NiPx@FePyOz core@shell NPs act as a colloidally stable, ready-to-use, and excellent OER active transition metal phosphide-based catalyst.

Copper-Catalyzed Tandem Dehydrocyanation and [3+2] Cyclo­addition Reactions of Phenacylmalononitriles: Regioselective Synthesis of Functionalized 4-Benzoyl-5-cyanopyrazoles under Mild Conditions

Synthesis ◽  
2020 ◽  
Vol 52 (09) ◽  
pp. 1379-1386 ◽  
Author(s):  
Issa Yavari ◽  
Omid Khaledian
Keyword(s):  
Cycloaddition Reaction ◽  
Complexing Agent ◽  
Ambient Conditions ◽  
Weak Base ◽  
Mild Conditions ◽  
Hydrazonoyl Chlorides ◽  
Wide Range ◽  
Nitrile Imines ◽  
In Situ Generation

A novel copper-catalyzed [3+2] cycloaddition reaction with concomitant in situ generation of benzoylacrylonitriles and nitrile imines from phenacylmalononitriles and hydrazonoyl chlorides, respectively, is reported. The reaction was performed using copper(I) chloride as catalyst and N-methylimidazole as a clean complexing agent/weak base to afford the functionalized 4-benzoyl-5-cyanopyrazoles in moderate to good yields and excellent regioselectivity under ambient conditions. This method provides rapid access to a wide range of highly functionalized 4-benzoyl-5-cyanopyrazoles.

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