Mechanism for O–O Bond Formation via Radical Coupling of Metal and Ligand Based Radicals: A New Pathway

2018 ◽  
Vol 140 (42) ◽  
pp. 13538-13541 ◽  
Author(s):  
Yulia Pushkar ◽  
Yuliana Pineda-Galvan ◽  
Alireza K. Ravari ◽  
Tatiana Otroshchenko ◽  
Daniel A. Hartzler
Keyword(s):  
Bond Formation ◽  
Radical Coupling

scholarly journals Selective C–O bond formation via a photocatalytic radical coupling strategy: access to perfluoroalkoxylated (ORF) arenes and heteroarenes

2017 ◽  
Vol 8 (9) ◽  
pp. 6066-6070 ◽  
Author(s):  
Johnny W. Lee ◽  
Dominique N. Spiegowski ◽  
Ming-Yu Ngai
Keyword(s):  
Bond Formation ◽  
Radical Coupling ◽  
Coupling Strategy

Synthesis of perfluoroalkoxylated (hetero)arenes (Ar–ORF) from readily available perfluoroalkyl iodides (RF–I) through photocatalytic selective O–RF bond formation.

Recent Advances in Photocatalytic C–N Bond Coupling Reactions

Synthesis ◽  
2020 ◽  
Author(s):  
Wing-Yiu Yu ◽  
Chun-Ming Chan ◽  
Yip-Chi Chow
Keyword(s):  
Carbonyl Compounds ◽  
Bond Formation ◽  
Coupling Reactions ◽  
Amino Groups ◽  
Cyclization Reactions ◽  
Radical Coupling ◽  
Synthetic Intermediates ◽  
Photocatalytic Reactions ◽  
Metal Catalyzed ◽  
Pharmaceutical Agents

Catalytic C–N bond formation is one of the major research topics in synthetic chemistry owing to the ubiquity of amino groups in natural products, synthetic intermediates and pharmaceutical agents. In parallel with well-established metal-catalyzed C–N bond coupling protocols, photocatalytic reactions have recently emerged as efficient and selective alternatives for the construction of C–N bonds. In this review, the progress made on photocatalytic C–N bond coupling reactions between 2012 and February 2020 is summarized.1 Introduction1.1 General Mechanisms for Photoredox Catalysis1.2 Pioneering Work2 C(sp2)–N Bond Formation2.1 Protocols Involving an External Oxidant2.2 Oxidant-Free Protocols3 C(sp3)–N Bond Formation3.1 Direct Radical–Radical Coupling3.2 Addition Reactions to Alkenes3.3 Reductive Amination of Carbonyl Compounds3.4 Decarboxylative Amination4 Cyclization Reactions4.1 C(sp2)–N Heterocycle Formation4.2 C(sp3)–N Heterocycle Formation5 Other Examples6 Conclusion and Outlook

Radical coupling for directed C–C/C–S bond formation in the reaction of Cp*IrS2C2B10H10 with 1-azido-3-nitrobenzene

2014 ◽  
Vol 43 (13) ◽  
pp. 4962 ◽  
Author(s):  
Wei Zhong ◽  
Qibai Jiang ◽  
Qian Zhang ◽  
Yi Shang ◽  
Hong Yan ◽  
...  
Keyword(s):  
Bond Formation ◽  
Radical Coupling

O–O bond formation in ruthenium-catalyzed water oxidation: single-site nucleophilic attack vs. O–O radical coupling

2017 ◽  
Vol 46 (20) ◽  
pp. 6170-6193 ◽  
Author(s):  
David W. Shaffer ◽  
Yan Xie ◽  
Javier J. Concepcion
Keyword(s):  
Water Oxidation ◽  
Bond Formation ◽  
Single Site ◽  
Nucleophilic Attack ◽  
Radical Coupling ◽  
Molecular Catalysts

A review of water oxidation by ruthenium-based molecular catalysts, with emphasis on the mechanism of O–O bond formation.

scholarly journals Hydrazine Formation via NiIII-NH2 Radical Coupling in Ni-Mediated Ammonia Oxidation

2020 ◽  
Author(s):  
Nina Gu ◽  
Paul H. Oyala ◽  
Jonas Peters
Keyword(s):  
Water Oxidation ◽  
Ammonia Oxidation ◽  
Bond Formation ◽  
Oxidation States ◽  
Bond Forming ◽  
Radical Coupling ◽  
Multiply Bonded ◽  
Ni Species ◽  
Oxidation Mechanisms ◽  
Metal Ligand

<p>Given the diverse mechanistic possibilities for the overall 6e<sup>-</sup>/6H<sup>+</sup> transformation of ammonia to dinitrogen, identification of M(NH<sub>x</sub>) intermediates involved in N–N bond formation is a central mechanistic challenge. In analogy to water oxidation mechanisms, which widely invoke metal oxo intermediates, metal imide and nitride intermediates have commonly been proposed for ammonia oxidation, and stoichiometric demonstration of N–N bond formation from these metal-ligand multiply bonded species is well-precedented. In contrast, while the homocoupling of M–NH<sub>2</sub> species to form hydrazine has been hypothesized as the key N–N bond forming step in certain molecular ammonia oxidation systems, well-defined examples of this transformation from M–NH<sub>2</sub> complexes are essentially without precedent. This work reports the first example of net ammonia oxidation mediated by a molecular Ni species, a transformation carried out via formal Ni<sup>II</sup>/Ni<sup>III</sup> oxidation states. The available data are consistent with a Ni<sup>III</sup>–NH<sub>2</sub> intermediate featuring substantial spin at N undergoing N–N bond formation to generate a Ni<sup>II</sup><sub>2</sub>(N<sub>2</sub>H<sub>4</sub>) complex. Additional and structurally unusual Ni<sub>x</sub>(N<sub>y</sub>H<sub>z</sub>) species – including a Ni<sub>2</sub>(<i>trans</i>-N<sub>2</sub>H<sub>2</sub>) complex – are characterized and studied as intermediates in the Ni-mediated ammonia oxidation cycle described herein.</p>

Visible light-driven selective carbon–carbon bond formation for the production of vicinal diols

2020 ◽  
Vol 4 (11) ◽  
pp. 5488-5492
Author(s):  
Peng Bai ◽  
Xinli Tong ◽  
Yiqi Gao ◽  
Song Xue
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Bond Formation ◽  
Light Irradiation ◽  
Carbon Bond ◽  
Benzylic Alcohols ◽  
Radical Coupling ◽  
Carbon Carbon Bond ◽  
Visible Light Driven ◽  
Vicinal Diols

A green and sustainable production of vicinal diols via the photocatalytic radical coupling of benzylic alcohols has been developed under visible light irradiation.

scholarly journals Hydrazine Formation via NiIII-NH2 Radical Coupling in Ni-Mediated Ammonia Oxidation

2020 ◽  
Author(s):  
Nina Gu ◽  
Paul H. Oyala ◽  
Jonas Peters
Keyword(s):  
Water Oxidation ◽  
Ammonia Oxidation ◽  
Bond Formation ◽  
Oxidation States ◽  
Bond Forming ◽  
Radical Coupling ◽  
Multiply Bonded ◽  
Ni Species ◽  
Oxidation Mechanisms ◽  
Metal Ligand

<p>Given the diverse mechanistic possibilities for the overall 6e<sup>-</sup>/6H<sup>+</sup> transformation of ammonia to dinitrogen, identification of M(NH<sub>x</sub>) intermediates involved in N–N bond formation is a central mechanistic challenge. In analogy to water oxidation mechanisms, which widely invoke metal oxo intermediates, metal imide and nitride intermediates have commonly been proposed for ammonia oxidation, and stoichiometric demonstration of N–N bond formation from these metal-ligand multiply bonded species is well-precedented. In contrast, while the homocoupling of M–NH<sub>2</sub> species to form hydrazine has been hypothesized as the key N–N bond forming step in certain molecular ammonia oxidation systems, well-defined examples of this transformation from M–NH<sub>2</sub> complexes are essentially without precedent. This work reports the first example of net ammonia oxidation mediated by a molecular Ni species, a transformation carried out via formal Ni<sup>II</sup>/Ni<sup>III</sup> oxidation states. The available data are consistent with a Ni<sup>III</sup>–NH<sub>2</sub> intermediate featuring substantial spin at N undergoing N–N bond formation to generate a Ni<sup>II</sup><sub>2</sub>(N<sub>2</sub>H<sub>4</sub>) complex. Additional and structurally unusual Ni<sub>x</sub>(N<sub>y</sub>H<sub>z</sub>) species – including a Ni<sub>2</sub>(<i>trans</i>-N<sub>2</sub>H<sub>2</sub>) complex – are characterized and studied as intermediates in the Ni-mediated ammonia oxidation cycle described herein.</p>

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