Copper Photoredox Catalyzed A3’ Coupling of Arylamines, Terminal Alkynes, and Alcohols through a Hydrogen Atom Transfer Process

2019 ◽  
Vol 58 (12) ◽  
pp. 3838-3842 ◽  
Author(s):  
Arunachalam Sagadevan ◽  
V. Kishore Kumar Pampana ◽  
Kuo Chu Hwang
Keyword(s):  
Hydrogen Atom ◽  
Transfer Process ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Terminal Alkynes ◽  
A3 Coupling

Carbonylative Coupling of Simple Alkanes and Alkenes Enabled by Organic Photoredox Catalysis

2021 ◽  
Author(s):  
Ling Chen ◽  
Jing Hou ◽  
Ming Zheng ◽  
Le-Wu Zhan ◽  
Wan-Ying Tang ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Visible Light ◽  
Transfer Process ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Photoredox Catalysis ◽  
Visible Light Driven

A visible-light-driven direct carbonylative coupling of simple alkanes and alkenes via the combination of the hydrogen atom transfer process and photoredox catalysis has been demonstrated. Employing the N-alkoxyazinium salt as...

Ion-molecule reactions in acetone-water mixtures

1966 ◽  
Vol 19 (1) ◽  
pp. 59 ◽  
Author(s):  
Souza BC de ◽  
JH Green
Keyword(s):  
Hydrogen Atom ◽  
Proton Transfer ◽  
Transfer Process ◽  
Hydrogen Atom Transfer ◽  
Mass Spectrometric ◽  
Transfer Mechanism ◽  
Atom Transfer ◽  
Ion Molecule Reactions ◽  
Acetone Water

Mass-spectrometric studies of ion-molecule reactions in acetone-water mixtures at 70 eV and 20 eV electron energies are described. The results provide evidence in favour of the proton transfer mechanism rather than for a hydrogen atom transfer process for the production of M + 1 ions.

The water–boryl radical as a proton-coupled electron transfer reagent for carbon dioxide, formic acid, and formaldehyde — Theoretical approach

2013 ◽  
Vol 91 (2) ◽  
pp. 155-168
Author(s):  
Waled Tantawy ◽  
Ahmed Hashem ◽  
Nabil Yousif ◽  
Eman Flefel
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Bond ◽  
Electron Transfer ◽  
Hydrogen Atom ◽  
Transfer Process ◽  
Carbonyl Compounds ◽  
Hydrogen Atom Transfer ◽  
Transfer Reactions ◽  
Atom Transfer ◽  
Proton Coupled Electron Transfer

The thermochemistry of the hydrogen atom transfer reactions from the H2O–BX2 radical system (X = H, CH3, NH2, OH, F) to carbon dioxide, formic acid, and (or) formaldehyde, which produce hydroxyformyl, dihydroxymethyl, and hydroxymethyl radicals, respectively, were investigated theoretically at ROMP2/6–311+G(3DF,2P)//UB3LYP/6–31G(D) and UG3(MP2)-RAD levels of theory. Surprisingly, in the cases of a strong Lewis acid (X = H, CH3, F), the spin transfer process from the water–boryl radical to the carbonyl compounds was barrier-free and associated with a dramatic reduction in the B–H bond dissociation energy (BDE) relative to that of isolated water–borane complexes. Examining the coordinates of these reactions revealed that the entire hydrogen atom transfer process is governed by the proton-coupled electron transfer (PCET) mechanism. Hence, the elucidated mechanism has been applied in the cases of weak Lewis acids (X = NH2, OH), and the variation in the accompanied activation energy was attributed to the stereoelectronic effect interplaying in CO2 and HCOOH compared with HCHO. We ascribed the overall mechanism as a SA-induced five-center cyclic PCET, in which the proton transfers across the so-called complexation-induced hydrogen bond (CIHB) channel, while the SOMOB–LUMOC=O′ interaction is responsible for the electron migration process. Owing to previous reports that interrelate the hydrogen-bonding and the rate of proton-coupled electron-transfer reactions, we postulated that “the rate of the PCET reaction is expected to be promoted by the covalency of the hydrogen bond, and any factor that enhances this covalency could be considered an activator of the PCET process.” This postulate could be considered a good rationale for the lack of a barrier associated with the hydrogen atom transfer from the water-boryl radical system to the carbonyl compounds. Light has been shed on the water–boryl radical reagent from the thermodynamic perspective.

Isomérisation des radicaux insaturés. III. Radicaux α,α,β-,α,β,γ- et α,α,γ-triméthallyles

1985 ◽  
Vol 63 (11) ◽  
pp. 3168-3173 ◽  
Author(s):  
Hélène Deslauriers ◽  
Guy J. Collin
Keyword(s):  
Hydrogen Atom ◽  
Gas Phase ◽  
Internal Energy ◽  
Transfer Process ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer

α,α,β-, α,β,γ-, and α,α,γ-trimethallyl radicals have been generated in the 147.0–nm gas phase photolysis of 2,3,3-trimethyl-1-butene, 3,4-dimethyl-2-pentene, and 2,4-dimethyl-2-pentene, respectively. Under these conditions, the majority of allyl radicals have an internal energy sufficient for further decomposition: they give rise to the formation of various 1,3-dienes and small amounts of either 1,2- or 2,3-dienes. An internal sigmatropic 1,4-hydrogen atom transfer process is part of the proposed mechanism to explain such products. Moreover, the fragmentation of the trimethyl substituted allyl radicals involves the split of one β(C—C) bond, then one β(C—H), and, to a lesser extent, one central C—CH3 bond.

Photo-induced proton coupled electron transfer from a benzophenone ‘antenna’ to an isoindoline nitroxide

RSC Advances ◽  
2015 ◽  
Vol 5 (116) ◽  
pp. 95598-95603 ◽  
Author(s):  
Jason C. Morris ◽  
Liam A. Walsh ◽  
Brunell A. Gomes ◽  
Didier Gigmes ◽  
Kathryn E. Fairfull-Smith ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Energy Transfer ◽  
Excited State ◽  
Hydrogen Atom ◽  
Transfer Process ◽  
Energy Transfer Process ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Proton Coupled Electron Transfer

When exposed to light, a novel nitroxide-benzophenone hybrid will undergo an energy transfer process whereby the nitroxide enters an excited state which induces an efficient hydrogen atom transfer from unactivated alkanes.

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