scholarly journals Metal-free direct alkylation of unfunctionalized allylic/benzylic sp3C–H bonds via photoredox induced radical cation deprotonation

2017 ◽  
Vol 8 (6) ◽  
pp. 4654-4659 ◽  
Author(s):  
Rong Zhou ◽  
Haiwang Liu ◽  
Hairong Tao ◽  
Xingjian Yu ◽  
Jie Wu
Keyword(s):  
Radical Cation ◽  
Metal Free

An unprecendented direct alkylation of unfunctionalized allylic/benzylic sp3C–H bondsviaphotoredox induced radical cation deprotonation is disclosed.

scholarly journals Metal-Free α-C(sp3)–H Functionalized Oxidative Cyclization of Tertiary N,N-Diaryl Amino Alcohols: Theoretical Approach for Mechanistic Pathway

2017 ◽  
Author(s):  
Zakir Ullah ◽  
Mihyun Kim
Keyword(s):  
Free Energy ◽  
Radical Cation ◽  
Theoretical Approach ◽  
Dft Calculation ◽  
Amino Alcohols ◽  
Oxidative Cyclization ◽  
Solution Phase ◽  
Ionic Mechanism ◽  
Metal Free ◽  
Mechanistic Pathway

The mechanistic pathway of TEMPO/I2-mediated oxidative cyclization of N,N-diaryl amino alcohols 1 is investigated in this study. Based on our direct empirical experiments, three key intermediates (the aminium radical cation 3, the α-aminoalkyl radical 4, and the iminium 5), four kind reactive species (radical TEMPO, cationic TEMPO, TEMPO-I and iodo radical) and three kind pathways (1. SET/PCET mechanism, 2. HAT/1,6-H transfer mechanism, 3. Ionic mechanism) were assumed. Under the assumption, nine free energy diagrams are acquired through DFT calculation. From the comparison of the solution phase free energy, some possibility can be excluded and then the chosen plausible mechanisms are concretized with the more stable intermediate 7.

scholarly journals Isolation of base stabilized fluoroborylene and its radical cation

2019 ◽  
Vol 48 (24) ◽  
pp. 8551-8555 ◽  
Author(s):  
Samir Kumar Sarkar ◽  
Mujahuddin M. Siddiqui ◽  
Subrata Kundu ◽  
Munmun Ghosh ◽  
Johannes Kretsch ◽  
...  
Keyword(s):  
Radical Cation ◽  
Synthesis And Characterization ◽  
Metal Free

The synthesis and characterization of metal-free fluoroborylene [(Me-cAAC)2BF] (1) is reported.

The Shadow Widths of Very Small Particles are Formed Independently of the Metal Cap Build Up on the Particle

1981 ◽  
Vol 39 ◽  
pp. 568-569
Author(s):  
George C. Ruben
Keyword(s):  
Gold Particle ◽  
Film Surface ◽  
Small Particles ◽  
Geometric Process ◽  
Metal Free ◽  
Shadow Area

The formation of shadows behind small particles has been thought to be a geometric process (GP) where the metal cap build up on the particle creates a shadow width the same size as or larger than the particle. This GP cannot explain why gold particle shadow widths are generally larger than the gold particle and may have no appreciable metal cap build up (fig. 1). Ruben and Telford have suggested that particle shadow widths are formed by the width dependent deflection of shadow metal (SM) lateral to and infront of the particle. The trajectory of the deflected SM is determined by the incoming shadow angle (45°). Since there can be up to 1.4 times (at 45°) more SM directly striking the particle than the film surface, a ridge of metal nuclei lateral to and infront of the particle can be formed. This ridge in turn can prevent some SM from directly landing in the metal free shadow area. However, the SM that does land in the shadow area (not blocked by the particle or its ridge) does not stick and apparently surface migrates into the SM film behind the particle.

Recent advancement in the electrocatalytic synthesis of ammonia

Nanoscale ◽  
2020 ◽  
Vol 12 (15) ◽  
pp. 8065-8094 ◽  
Author(s):  
Xudong Wen ◽  
Jingqi Guan
Keyword(s):  
Metal Oxide ◽  
Oxide Catalysts ◽  
Single Atom ◽  
Metal Oxide Catalysts ◽  
Metal Free ◽  
Recent Advancement ◽  
Nanocomposite Catalysts

Different kinds of electrocatalysts used in NRR electrocatalysis (including single atom catalysts, metal oxide catalysts, nanocomposite catalysts, and metal free catalysts) are introduced.

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.

Deaminative carbonylative thioesterification of activated alkylamines with thiophenols under transition-metal-free conditions

2021 ◽  
Author(s):  
Fengqian Zhao ◽  
Xiao-Feng Wu
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Metal Free

A transition-metal-free radical carbonylation of activated alkylamines with thiophenols has been successfully developed. Various thioesters were selectively produced with moderate to good yields.

The electronic properties of a radical cation salt of bis-ethylenedioxodibenzofuran, [(bEDODBF)5 (AsF6)2(CH2Cl 2)0.2]

1988 ◽  
Vol 49 (4) ◽  
pp. 667-673 ◽  
Author(s):  
S. Söderholm ◽  
J. Hellberg ◽  
G. Ahlgren ◽  
M. Krebs ◽  
J.U. von Schütz ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Radical Cation ◽  
Radical Cation Salt

Stereodivergent Alkyne Hydrofluorination Using a Simple Practical Reagent

2020 ◽  
Author(s):  
Rui Guo ◽  
Xiaotian Qi ◽  
Hengye Xiang ◽  
Paul Geaneoates ◽  
Ruihan Wang ◽  
...  
Keyword(s):  
Bond Formation ◽  
Biologically Active ◽  
Dft Studies ◽  
Thermodynamic Control ◽  
Important Goal ◽  
Peptide Bonds ◽  
Metal Free ◽  
Vinyl Cation ◽  
E And Z Isomers ◽  
Vinyl Fluorides

Vinyl fluorides play an important role in drug development as they serve as bioisosteres for peptide bonds and are found in a range of biologically active molecules. The discovery of safe, general and practical procedures to prepare vinyl fluorides remains an important goal and challenge for synthetic chemistry. Here we introduce an inexpensive and easily-handled reagent and report simple, scalable, and metal-free protocols for the regioselective and stereodivergent hydrofluorination of alkynes to access both the E and Z isomers of vinyl fluorides. These conditions were suitable for a diverse collection of alkynes, including several highly-functionalized pharmaceutical derivatives. Mechanistic and DFT studies support C–F bond formation through a vinyl cation intermediate, with the (E)- and (Z)-hydrofluorination products forming under kinetic and thermodynamic control, respectively.<br>

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