scholarly journals Diazaphosphinanes as hydride, hydrogen atom, proton or electron donors under transition-metal-free conditions: thermodynamics, kinetics, and synthetic applications

2020 ◽  
Vol 11 (14) ◽  
pp. 3672-3679 ◽  
Author(s):  
Jingjing Zhang ◽  
Jin-Dong Yang ◽  
Jin-Pei Cheng
Keyword(s):  
Hydrogen Atom ◽  
Transition Metal ◽  
Proton Donor ◽  
Electron Donors ◽  
Metal Free ◽  
Hydride Hydrogen

A new 1,3,2-diazaphosphinane, serving as a formal hydride, hydrogen-atom or proton donor without transition-metal mediation was exploited thermodynamically and kinetically. And, its promising potentials in versatile syntheses have been demonstrated.

scholarly journals Transition-metal-free C(sp3)–H/C(sp3)–H dehydrogenative coupling of saturated heterocycles with N-benzyl imines

2020 ◽  
Vol 11 (29) ◽  
pp. 7619-7625 ◽  
Author(s):  
Zhengfen Liu ◽  
Minyan Li ◽  
Guogang Deng ◽  
Wanshi Wei ◽  
Ping Feng ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Transition Metal ◽  
Electron Donors ◽  
Metal Free ◽  
Aryl Radicals ◽  
Dehydrogenative Coupling ◽  
Saturated Heterocycles

A unique transition-metal-free C(sp3)–H/C(sp3)–H dehydrocoupling of N-benzylimines with saturated heterocycles is presented using 2-azaallyl anions as super electron donors to initiate the generation of hydrogen atom abstracting aryl radicals.

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

scholarly journals SET activation of nitroarenes by 2-azaallyl anions as a straightforward access to 2,5-dihydro-1,2,4-oxadiazoles

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Dong Zou ◽  
Lishe Gan ◽  
Fan Yang ◽  
Huan Wang ◽  
Youge Pu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Experimental Evidence ◽  
Radical Anion ◽  
Reaction Pathway ◽  
Cycloaddition Reaction ◽  
Electron Donors ◽  
Ring Closure ◽  
Computational Studies ◽  
Metal Free ◽  
Radical Coupling

AbstractThe use of nitroarenes as amino sources in synthesis is challenging. Herein is reported an unusual, straightforward, and transition metal-free method for the net [3 + 2]-cycloaddition reaction of 2-azaallyl anions with nitroarenes. The products of this reaction are diverse 2,5-dihydro-1,2,4-oxadiazoles (>40 examples, up to 95% yield). This method does not require an external reductant to reduce nitroarenes, nor does it employ nitrosoarenes, which are often used in N–O cycloadditions. Instead, it is proposed that the 2-azaallyl anions, which behave as super electron donors (SEDs), deliver an electron to the nitroarene to generate a nitroarene radical anion. A downstream 2-azaallyl radical coupling with a newly formed nitrosoarene is followed by ring closure to afford the observed products. This proposed reaction pathway is supported by computational studies and experimental evidence. Overall, this method uses readily available materials, is green, and exhibits a broad scope.

scholarly journals Transition-Metal-Free Radical C(sp3)–C(sp2) and C(sp3)–C(sp3) Coupling Enabled by 2-Azaallyls as Super-Electron-Donors and Coupling-Partners

2017 ◽  
Vol 139 (45) ◽  
pp. 16327-16333 ◽  
Author(s):  
Minyan Li ◽  
Simon Berritt ◽  
Lucas Matuszewski ◽  
Guogang Deng ◽  
Ana Pascual-Escudero ◽  
...  
Keyword(s):  
Free Radical ◽  
Transition Metal ◽  
Electron Donors ◽  
Metal Free

scholarly journals Organic super-electron-donors: initiators in transition metal-free haloarene–arene coupling

2014 ◽  
Vol 5 (2) ◽  
pp. 476-482 ◽  
Author(s):  
Shengze Zhou ◽  
Greg M. Anderson ◽  
Bhaskar Mondal ◽  
Eswararao Doni ◽  
Vicki Ironmonger ◽  
...  
Keyword(s):  
Transition Metal ◽  
Electron Donors ◽  
Metal Free

Transition-metal-free radical relay cyclization of vinyl azides with 1,4-dihydropyridines involving a 1,5-hydrogen-atom transfer: access to α-tetralone scaffolds

2020 ◽  
Vol 7 (22) ◽  
pp. 3638-3647
Author(s):  
Yangzhen Liao ◽  
Yu Ran ◽  
Guijun Liu ◽  
Peijun Liu ◽  
Xiaozu Liu
Keyword(s):  
Free Radical ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Atom Transfer ◽  
Metal Free ◽  
Vinyl Azides

The remote C(sp3)–H functionalization enabled by a radical-mediated 1,5-hydrogen-atom transfer (HAT) process using vinyl azides and 1,4-dihydropyridines as precursors has been described.

Direct Cyclization of Alkenyl Thioester via Transition Metal‐hydrogen Atom Transfer/radical‐polar Crossover Mechanism

2019 ◽  
Author(s):  
Shiori Date ◽  
Kensei Hamasaki ◽  
Karen Sunagawa ◽  
Hiroki Koyama ◽  
Chikayoshi Sebe ◽  
...  
Keyword(s):  
Natural Products ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Synthetic Method ◽  
Atom Transfer ◽  
Reaction Conditions ◽  
Hydride Hydrogen ◽  
Sulfur Heterocycles ◽  
One Step

<div>We report here a catalytic, Markovnikov selective, and scalable synthetic method for the synthesis of saturated sulfur heterocycles, which are found in the structures of pharmaceuticals and natural products, in one step from an alkenyl thioester. Unlike a potentially labile alkenyl thiol, an alkenyl thioester is stable and easy to prepare. The powerful Co catalysis via a cobalt hydride hydrogen atom transfer and radical-polar crossover mechanism enabled simultaneous cyclization and deprotection. The substrate scope was expanded by the extensive optimization of the reaction conditions and tuning of the thioester unit.</div>

Transition-Metal-Free C(sp3)–H Coupling of Cycloalkanes Enabled by Single-Electron Transfer and Hydrogen Atom Transfer

2021 ◽  
Vol 23 (5) ◽  
pp. 1714-1719
Author(s):  
Linlin Zhang ◽  
Zhengfen Liu ◽  
Xun Tian ◽  
Yujin Zi ◽  
Shengzu Duan ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Hydrogen Atom ◽  
Transition Metal ◽  
Hydrogen Atom Transfer ◽  
Single Electron ◽  
Atom Transfer ◽  
Single Electron Transfer ◽  
Metal Free

scholarly journals Transition-Metal-Free and Visible-Light-Mediated Desulfonylation and Dehalogenation Reactions: Hantzsch Ester Anion as Electron and Hydrogen Atom Donor

2020 ◽  
Vol 85 (21) ◽  
pp. 13481-13494
Author(s):  
Micaela D. Heredia ◽  
Walter D. Guerra ◽  
Silvia M. Barolo ◽  
Santiago J. Fornasier ◽  
Roberto A. Rossi ◽  
...  
Keyword(s):  
Hydrogen Atom ◽  
Transition Metal ◽  
Visible Light ◽  
Metal Free

Transition-metal-free catalytic hydroboration reduction of amides to amines

2020 ◽  
Vol 7 (21) ◽  
pp. 3515-3520
Author(s):  
Wubing Yao ◽  
Jiali Wang ◽  
Aiguo Zhong ◽  
Shiliang Wang ◽  
Yinlin Shao
Keyword(s):  
Transition Metal ◽  
Selective Catalytic Reduction ◽  
Catalytic Reduction ◽  
Value Added ◽  
Metal Free

The selective catalytic reduction of amides to value-added amine products is a desirable but challenging transformation.

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