Synthesis and Photocleavage of Quinoline Methyl Ethers: A Mild and Efficient Method for the Selective Protection and Deprotection of the Alcohol Functionality

2016 ◽  
Vol 69 (7) ◽  
pp. 763
Author(s):  
Anthony A. Provatas ◽  
Gary A. Epling ◽  
James D. Stuart
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Methyl Ether ◽  
Efficient Method ◽  
Substitution Reaction ◽  
Radical Scavenger ◽  
Single Electron Transfer ◽  
Radical Intermediate ◽  
Strong Base ◽  
Selective Protection

The synthesis and photocleavage of quinolinyl methyl ether-protected alcohols is reported in this study. A variety of quinoline methyl chlorides were synthesized, and protection of the various alcohols was performed via a substitution reaction in the presence of a strong base. Photocleavage of the quinolinyl methyl ether moiety proceeded under visible light with the formation of the charged quinolinyl radical intermediate through a single-electron transfer in the presence of a photosensitizer dye leading to the deprotected alcohol in excellent yields. The utility of triethylamine as a sacrificial reductant and d-sorbitol as a radical scavenger were also investigated in this study.

scholarly journals Light-Driven Depolymerization of Native Lignin Enabled by Proton- Coupled Electron Transfer

2019 ◽  
Author(s):  
Suong Nguyen ◽  
Phillip Murray ◽  
Robert Knowles
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Bond Cleavage ◽  
Direct Conversion ◽  
Alkoxy Radical ◽  
Radical Intermediate ◽  
Polymer Backbone ◽  
Good Efficiency ◽  
Chemical Reagents ◽  
Proton Coupled Electron Transfer

<div><p>Here we report a catalytic, light-driven method for the redox-neutral depolymerization of native lignin biomass at ambient temperature. This transformation proceeds via a proton-coupled electron-transfer (PCET) activation of an alcohol O–H bond to generate a key alkoxy radical intermediate, which then drives the <i>β</i>-scission of a vicinal C–C bond. Notably, this depolymerization is driven solely by visible light irradiation, requiring no stoichiometric chemical reagents and producing no stoichiometric waste. This method exhibits good efficiency and excellent selectivity for the activation and fragmentation of <i>β</i>-O-4 linkages in the polymer backbone, even in the presence of numerous other PCET-active functional groups. DFT analysis suggests that the key C–C bond cleavage reactions produce non-equilibrium product distributions, driven by excited-state redox events. These results provide further evidence that visible-light photocatalysis can serve as a viable method for the direct conversion of lignin biomass into valuable arene feedstocks.</p></div>

scholarly journals Intermolecular oxyarylation of olefins with aryl halides and TEMPOH catalyzed by the phenolate anion under visible light

2020 ◽  
Vol 11 (27) ◽  
pp. 6996-7002
Author(s):  
Kangjiang Liang ◽  
Qian Liu ◽  
Lei Shen ◽  
Xipan Li ◽  
Delian Wei ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Aryl Halides ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Strong Reduction ◽  
Aryl Radicals ◽  
Reduction Potentials

The phenolate anion was developed as a new photocatalyst with strong reduction potentials (−3.16 V vs. SCE) to reduction of aryl halides to aryl radicals through single electron transfer.

scholarly journals Recent application of visible-light induced radicals in C–S bond formation

RSC Advances ◽  
2020 ◽  
Vol 10 (34) ◽  
pp. 20046-20056 ◽  
Author(s):  
Vishal Srivastava ◽  
Pravin K. Singh ◽  
Arjita Srivastava ◽  
Praveen P. Singh
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Organic Compounds ◽  
High Efficiency ◽  
Bond Formation ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Recent Application

The sulphur centered radicals, produced from various organic compounds, in high efficiency by single-electron-transfer (SET) oxidation.

Earth-Abundant Cobalt based photocatalyst: Visible light induced direct (Het)Arene C-H arylation and CO2 capture

2022 ◽  
Author(s):  
Pooja Rana ◽  
Bhawna Kaushik ◽  
Rashmi Gaur ◽  
Sriparna Dutta ◽  
Sneha Yadav ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Noble Metal ◽  
Co2 Capture ◽  
Room Temperature ◽  
Single Electron Transfer ◽  
Metal Free ◽  
Transfer Processes ◽  
Earth Abundant ◽  
Electron Transfer Processes

In this work, we have reported a noble metal free heterogeneous photocatalyst to carry out direct (Het)Arene C-H arylation and solvent-free CO2 capture via single-electron transfer processes at room temperature...

Visible-Light-Mediated Synthesis of Pyrazines from Vinyl Azides Utilizing a Photocascade Process

Synlett ◽  
2017 ◽  
Vol 28 (14) ◽  
pp. 1707-1714 ◽  
Author(s):  
Asik Hossain ◽  
Santosh Pagire ◽  
Oliver Reiser
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Convenient Method ◽  
Dual Energy ◽  
Visible Light Photocatalysis ◽  
Single Electron Transfer ◽  
Air Atmosphere ◽  
Sensitization Process ◽  
Energy And Electron Transfer ◽  
Vinyl Azides

A convenient method for the synthesis of substituted pyrazines from vinyl azides has been developed. This method is enabled by a dual-energy and electron-transfer strategy by visible-light photocatalysis. Initially, vinyl azides are activated by a triplet sensitization process from an excited ruthenium photocatalyst in the presence of water to form dihydropyrazines, followed by a single-electron-transfer (SET) process under oxygen (air) atmosphere that leads to the tetrasubstituted pyrazines in good to excellent yields.

Visible Light-Promoted Photocatalytic C-5 Carboxylation of 8-Aminoquinoline Amides and Sulfonamides via a Single Electron Transfer Pathway

2019 ◽  
Vol 84 (16) ◽  
pp. 9869-9896 ◽  
Author(s):  
Chiranjit Sen ◽  
Tapan Sahoo ◽  
Harshvardhan Singh ◽  
Eringathodi Suresh ◽  
Subhash Chandra Ghosh
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Electron Transfer Pathway

Visible-light-induced phenylchalcogenyl-oxygenation of allenes having aryl or electron withdrawing substituents with ambient air as a sole oxidant

2016 ◽  
Vol 14 (48) ◽  
pp. 11415-11425 ◽  
Author(s):  
Gullapalli Kumaraswamy ◽  
Swargam Vijaykumar ◽  
Kukkadapu Ankamma ◽  
Vykunthapu Narayanarao
Keyword(s):  
Electron Transfer ◽  
Visible Light ◽  
Transfer Process ◽  
Stereoselective Synthesis ◽  
Ambient Air ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Electron Transfer Process ◽  
Electron Withdrawing Substituents

The stereoselective synthesis of α-phenylselenyl- or telluryl β-aryl acrylaldehydes/ketones from aryl allenes/1,3-diarylallene by an oxidative photo-induced single electron transfer process using benign ambient air as a sole oxidant was achieved.

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