Photoredox β-thiol-α-carbonylation of enones accompanied by unexpected Csp2–C(CO) bond cleavage

2020 ◽  
Vol 18 (38) ◽  
pp. 7549-7553
Author(s):  
Rui Ma ◽  
Jie Feng ◽  
Kuili Zhang ◽  
Beichen Zhang ◽  
Ding Du
Keyword(s):  
Visible Light ◽  
Bond Cleavage

An olefinic difunctionalization method of enones was presented here via aerobic visible-light catalysis.

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>

Visible-Light-Driven Selective Alkenyl C–P Bond Cleavage of Allenylphosphine Oxides

2019 ◽  
Vol 21 (7) ◽  
pp. 1994-1998 ◽  
Author(s):  
Kai Wei ◽  
Kai Luo ◽  
Fang Liu ◽  
Lei Wu ◽  
Li-Zhu Wu
Keyword(s):  
Visible Light ◽  
Bond Cleavage ◽  
Visible Light Driven

Visible Light-Promoted Metal-Free Reduction of Organohalides by 2-Naphthyl or 2-Hydroxynaphthyl-Substituted 1,3-Dimethylbenzimidazolines

2015 ◽  
Vol 68 (11) ◽  
pp. 1648 ◽  
Author(s):  
Eietsu Hasegawa ◽  
Kazuma Mori ◽  
Shiori Tsuji ◽  
Kazuki Nemoto ◽  
Taku Ohta ◽  
...  
Keyword(s):  
Visible Light ◽  
Halogen Bond ◽  
Light Emitting Diode ◽  
Bond Cleavage ◽  
Ring Expansion ◽  
Single Electron Transfer ◽  
Reduction Reactions ◽  
Light Emitting ◽  
Reducing Ability ◽  
Carbon Radicals

The visible light-promoted reduction reactions of some organohalides were investigated using 2-aryl-1,3-dimethylbenzimidazolines (Ar-DMBIH) possessing 2-naphthyl or 2-hydroxynaphthyl substituents. In these reduction reactions, single-electron transfer from photo-excited Ar-DMBIH, attained by Xe lamp irradiation through an appropriate glass-filter (λ > 390 nm), to the halide substrates leads to the carbon–halogen bond cleavage, followed by the rearrangements of the formed carbon radicals such as 5-exo hexenyl cyclization and the Dowd–Beckwith ring expansion. Addition of 1,8-diazabicyclo[5.4.0]undec-7-ene was found to enhance the reducing ability of hydroxynaphthyl-substituted DMBIH. A household white light-emitting diode was also used as a light source for these reactions.

Visible-light-induced dual C–C bond formation via selective C(sp3)–H bond cleavage: efficient access to alkylated oxindoles from activated alkenes and simple ethers under metal-free conditions

2017 ◽  
Vol 19 (7) ◽  
pp. 1732-1739 ◽  
Author(s):  
Dong Xia ◽  
Yang Li ◽  
Tao Miao ◽  
Pinhua Li ◽  
Lei Wang
Keyword(s):  
Visible Light ◽  
Bond Cleavage ◽  
Bond Formation ◽  
Metal Free ◽  
Efficient Access ◽  
Oxidative Difunctionalization

A visible-light-induced oxidative difunctionalization of activated alkenes with simple ethersviaselective C(sp3)–H bond cleavage and dual C–C bond formation was developed.

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