Direct and Unified Access to Carbon Radicals from Aliphatic Alcohols by Cost‐Efficient Titanium‐Mediated Homolytic C–OH Bond Cleavage

2022 ◽  
Author(s):  
Takuya Suga ◽  
Yuuki Takahashi ◽  
Chinatsu Miki ◽  
Yutaka Ukaji
Keyword(s):  
Bond Cleavage ◽  
Aliphatic Alcohols ◽  
Carbon Radicals ◽  
Cost Efficient

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.

scholarly journals Asymmetric three-component olefin dicarbofunctionalization enabled by photoredox and copper dual catalysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Peng-Zi Wang ◽  
Yuan Gao ◽  
Jun Chen ◽  
Xiao-Die Huan ◽  
Wen-Jing Xiao ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Cross Coupling ◽  
Optically Active ◽  
Extensive Investigation ◽  
Diverse Range ◽  
Mild Conditions ◽  
Redox Active ◽  
Carbon Radicals ◽  
Dual Catalysis

AbstractThe intermolecular three-component alkene vicinal dicarbofunctionalization (DCF) reaction allows installation of two different carbon fragments. Despite extensive investigation into its ionic chemistry, the enantioseletive radical-mediated versions of DCF reactions remain largely unexplored. Herein, we report an intermolecular, enantioselective three-component radical vicinal dicarbofunctionalization reaction of olefins enabled by merger of radical addition and cross-coupling using photoredox and copper dual catalysis. Key to the success of this protocol relies on chemoselective addition of acyl and cyanoalkyl radicals, generated in situ from the redox-active oxime esters by a photocatalytic N-centered iminyl radical-triggered C-C bond cleavage event, onto the alkenes to form new carbon radicals. Single electron metalation of such newly formed carbon radicals to TMSCN-derived L1Cu(II)(CN)2 complex leads to asymmetric cross-coupling. This three-component process proceeds under mild conditions, and tolerates a diverse range of functionalities and synthetic handles, leading to valuable optically active β–cyano ketones and alkyldinitriles, respectively, in a highly enantioselective manner (>60 examples, up to 97% ee).

scholarly journals Asymmetric Three-Component Olefin Dicarbofunctionalization Enabled by Photoredox and Copper Dual Catalysis

2020 ◽  
Author(s):  
Peng-Zi Wang ◽  
Yuan Gao ◽  
Jun Chen ◽  
Xiao-Die Huan ◽  
Wen-Jing Xiao ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Cross Coupling ◽  
Radical Addition ◽  
Optically Active ◽  
Diverse Range ◽  
Mild Conditions ◽  
Redox Active ◽  
Carbon Radicals ◽  
Dual Catalysis

<i>An intermolecular, enantioselective three-component radical vicinal dicarbofunctionalization reaction of olefins enabled by merger of radical addition and cross-coupling using photoredox and copper dual catalysis is presented here. Key to the success of this protocol relies on chemoselective addition of acyl and cyanoalkyl radicals, generated in situ from the redox-active oxime esters by a photocatalytic N-centered iminyl radical-triggered C-C bond cleavage event, onto the alkenes to form new carbon radicals. Single electron metalation of such newly formed carbon radicals to TMSCN-derived <b>L1</b>Cu(II)(CN)<sub>2</sub> complex leads to asymmetric cross-coupling. This three-component process proceeds under mild conditions, and tolerates a diverse range of functionalities and synthetic handles, leading to valuable optically active β–cyano ketones and alkyldinitriles, respectively, in a highly enantioselective manner (> 60 examples, up to 97% ee).</i>

scholarly journals Asymmetric Three-Component Olefin Dicarbofunctionalization Enabled by Photoredox and Copper Dual Catalysis

2020 ◽  
Author(s):  
Wen-Jing Xiao ◽  
Peng-Zi Wang ◽  
Yuan Gao ◽  
Xiao-Die Huan ◽  
Jun Chen ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Cross Coupling ◽  
Radical Addition ◽  
Optically Active ◽  
Diverse Range ◽  
Mild Conditions ◽  
Redox Active ◽  
Carbon Radicals ◽  
Dual Catalysis

Abstract An intermolecular, enantioselective three-component radical vicinal dicarbofunctionalization reaction of olefins enabled by merger of radical addition and cross-coupling using photoredox and copper dual catalysis is presented here. Key to the success of this protocol relies on chemoselective addition of acyl and cyanoalkyl radicals, generated in situ from the redox-active oxime esters by a photo-catalytic N-centered iminyl radical-triggered C-C bond cleavage event, onto the alkenes to form new carbon radicals. Single electron metalation of such newly formed carbon radicals to TMSCN-derived L1Cu(II)(CN)2 complex leads to asymmetric cross-coupling. This three-component process proceeds under mild conditions, and tolerates a diverse range of functionalities and synthetic handles, leading to valuable optically active β–cyano ketones and alkyldinitriles, respectively, in a highly enantioselective manner (> 60 examples, up to 97% ee).

scholarly journals Asymmetric Three-Component Olefin Dicarbofunctionalization Enabled by Photoredox and Copper Dual Catalysis

2020 ◽  
Author(s):  
Peng-Zi Wang ◽  
Yuan Gao ◽  
Jun Chen ◽  
Xiao-Die Huan ◽  
Wen-Jing Xiao ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Cross Coupling ◽  
Radical Addition ◽  
Optically Active ◽  
Diverse Range ◽  
Mild Conditions ◽  
Redox Active ◽  
Carbon Radicals ◽  
Dual Catalysis

<i>An intermolecular, enantioselective three-component radical vicinal dicarbofunctionalization reaction of olefins enabled by merger of radical addition and cross-coupling using photoredox and copper dual catalysis is presented here. Key to the success of this protocol relies on chemoselective addition of acyl and cyanoalkyl radicals, generated in situ from the redox-active oxime esters by a photocatalytic N-centered iminyl radical-triggered C-C bond cleavage event, onto the alkenes to form new carbon radicals. Single electron metalation of such newly formed carbon radicals to TMSCN-derived <b>L1</b>Cu(II)(CN)<sub>2</sub> complex leads to asymmetric cross-coupling. This three-component process proceeds under mild conditions, and tolerates a diverse range of functionalities and synthetic handles, leading to valuable optically active β–cyano ketones and alkyldinitriles, respectively, in a highly enantioselective manner (> 60 examples, up to 97% ee).</i>

Photocatalytic Neophyl Rearrangement and Reduction of Distal Carbon Radicals by Iminyl Radical-Mediated C−C Bond Cleavage

2018 ◽  
Vol 360 (18) ◽  
pp. 3601-3606 ◽  
Author(s):  
Xiao-Ye Yu ◽  
Peng-Zi Wang ◽  
Dong-Mei Yan ◽  
Bin Lu ◽  
Jia-Rong Chen ◽  
...  
Keyword(s):  
Bond Cleavage ◽  
Carbon Radicals
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