Visible-light-induced alkoxyl radical generation for inert chemical bond cleavage/functionalization

2018 ◽  
Vol 54 (48) ◽  
pp. 6105-6112 ◽  
Author(s):  
Kunfang Jia ◽  
Yiyun Chen
Keyword(s):  
Visible Light ◽  
Chemical Bond ◽  
Bond Cleavage ◽  
Alkoxyl Radical ◽  
Radical Generation

The recent advancements in inert C(sp3)–H, C(sp3)–C(sp3), and C(sp3)–X bond cleavage/functionalization by visible-light-induced alkoxyl radical generation are discussed.

Visible-light promoted γ-cyanoalkyl radical generation: three-component cyanopropylation/etherification of unactivated alkenes

2017 ◽  
Vol 53 (84) ◽  
pp. 11544-11547 ◽  
Author(s):  
Linyong Li ◽  
Haoguo Chen ◽  
Mingjing Mei ◽  
Lei Zhou
Keyword(s):  
Visible Light ◽  
Bond Cleavage ◽  
Alkyl Radicals ◽  
Radical Generation

A photoredox approach to generate distal cyano-substituted alkyl radicals through C–C bond cleavage of cyclobutanone oximes was developed.

Visible-Light Photosensitized Aryl and Alkyl Decarboxylative Carbon-Heteroatom and Carbon-Carbon Bond Formations

2019 ◽  
Author(s):  
Tuhin Patra ◽  
Satobhisha Mukherjee ◽  
Jiajia Ma ◽  
Felix Strieth-Kalthoff ◽  
Frank Glorius
Keyword(s):  
Energy Transfer ◽  
Visible Light ◽  
Alkyl Radical ◽  
General Strategy ◽  
Alkyl Radicals ◽  
Bond Forming ◽  
Radical Trapping ◽  
Carbon Carbon Bond ◽  
Radical Generation ◽  
Trapping Agent

<sub>A general strategy to access both aryl and alkyl radicals by photosensitized decarboxylation of the corresponding carboxylic acids esters has been developed. An energy transfer mediated homolysis of unsymmetrical sigma-bonds for a concerted fragmentation/decarboxylation process is involved. As a result, an independent aryl/alkyl radical generation step enables a series of key C-X and C-C bond forming reactions by simply changing the radical trapping agent.</sub>

Visible-Light-Promoted CC Bond Cleavage: Photocatalytic Generation of Iminium Ions and Amino Radicals

2012 ◽  
Vol 51 (32) ◽  
pp. 8050-8053 ◽  
Author(s):  
Shunyou Cai ◽  
Xinyang Zhao ◽  
Xinbo Wang ◽  
Qisong Liu ◽  
Zigang Li ◽  
...  
Keyword(s):  
Visible Light ◽  
Bond Cleavage ◽  
Iminium Ions

ChemInform Abstract: Oxygen Switch in Visible-Light Photoredox Catalysis: Radical Additions and Cyclizations and Unexpected C-C-Bond Cleavage Reactions.

ChemInform ◽  
2013 ◽  
Vol 44 (29) ◽  
pp. no-no
Author(s):  
Shaoqun Zhu ◽  
Arindam Das ◽  
Lan Bui ◽  
Hanjun Zhou ◽  
Dennis P. Curran ◽  
...  
Keyword(s):  
Visible Light ◽  
Bond Cleavage ◽  
Photoredox Catalysis ◽  
Cleavage Reactions

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>

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