Cyanation: a photochemical approach and applications in organic synthesis

Patel, Roshan I.; Sharma, Shivani; Sharma, Anuj

doi:10.1039/d1qo00162k

Cited by 53 publications

(21 citation statements)

References 245 publications

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“…These above results definitely confirmed that the reductive quenching cycle in Fig. 6a was the dominant pathway in the current transformation, which is different from the well-established oxidative quenching mechanism 61 , 75 , 76 .…”

Section: Resultssupporting

confidence: 61%

“…Finally, in both pathway the radical intermediate 10 may isomerize to allenyl radical 11 73 , 74 , which may bind with LCu II (CN) 2 , followed by reductive elimination to deliver allenenitrile 2 and regenerate the catalytically active species LCu I CN. Another possible pathway, 11 could abstract the CN group from LCu II (CN) 2 to afford allenenitrile 2 32 , 75 , 76 . The steric effect of R 1 , R 2 , and R 3 may play an important role in the reaction selectivity for forming 2 or 3 .…”

Section: Resultsmentioning

confidence: 99%

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Photo and copper dual catalysis for allene syntheses from propargylic derivatives via one-electron process

et al. 2022

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Different from the traditional two-electron oxidative addition-transmetalation-reductive elimination coupling strategy, visible light has been successfully integrated into transition metal-catalyzed coupling reaction of propargylic alcohol derivatives highly selectively forming allenenitriles: specifically speaking, visible light-mediated Cu-catalyzed cyanation of propargylic oxalates has been realized for the general, efficient, and exclusive syntheses of di-, tri, and tetra-substituted allenenitriles bearing various synthetically versatile functional groups. A set of mechanistic studies, including fluorescence quenching experiments, cyclic voltammetric measurements, radical trapping experiments, control experiments with different photocatalyst, and DFT calculation studies have proven that the current reaction proceeds via visible light-induced redox-neutral reductive quenching radical mechanism, which is a completely different approach as compared to the traditional transition metal-catalyzed two-electron oxidative addition processes.

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Section: Resultssupporting

confidence: 61%

Section: Resultsmentioning

confidence: 99%

Photo and copper dual catalysis for allene syntheses from propargylic derivatives via one-electron process

et al. 2022

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“…The cyanide group being effortlessly converted to various functional groups, is also a crucial organic scaffold. [32] They are largely present in different pharmaceutical drugs and bioactive molecules. [33] Regioselective C-3 cyanation of imidazo[1,2-a] pyridine core is reported previously.…”

Section: Cyanationmentioning

confidence: 99%

Ortho C−H Functionalization of 2‐Arylimidazo[1,2‐a]pyridines

Ghosh

Laru

Hajra

2021

The Chemical Record

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C−H activation and functionalization is quite promising in recent days as the strategy offers a go‐to general method for different bond formations and hence grants synthetic versatility. At the same time, imidazopyridine, a fused bicycle of imidazole moiety with pyridine ring, has a profound impact due to its ubiquitous and prodigious application in medicinal as well as material chemistry. The presence of N‐1 atom in 2‐arylImidazo[1,2‐a]pyridine facilitates the coordination with metal catalysts leading to the formation of ortho‐substituted products. This review summarizes all the articles on ortho C−H functionalization of 2‐arylImidazo[1,2‐a]pyridines published till August 2021.

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“…In particular, over the past few decades, transition-metal-catalyzed aryl halide cyanation has rapidly evolved into a convenient technology (Figure 1B) [9][10][11][12][13][14][15] . Despite tremendous advances in this field 16 , from the perspective of green chemical synthesis, this technology still needs to be more perfect. For example, when metal-or metalloid-bound cyanides (e.g., NaCN, KCN, TMSCN, and K 4 [Fe(CN) 3 ) are used, synthetic chemists are usually required to consider problems surrounding safety, reproducibility, and/or the production of excess metal waste 11,13,[17][18][19] .…”

Section: Introductionmentioning

confidence: 99%

Photoredox Catalysis Unlocks the Nickel-Catalyzed Cyanation of Aryl Halides under Benign Conditions

Jia

Liu

et al. 2022

CCS Chem

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The transition-metal-catalyzed cyanations of aryl halides are among the most used methods for synthesizing aryl nitriles. Despite tremendous advances, cyanating an aryl halide in a facile and benign fashion has generally been unsuccessful. The challenge for this significant transformation is the strong affinity of cyanide for metal centers, which makes organometallic catalysis elusive by hampering oxidative addition and reductive elimination. Herein, we demonstrate for the first time that photoredox/nickel-catalyzed cyanations of aryl halides are readily enabled by visible light, in which Ni(II) species are transiently oxidized to Ni(III) species, thereby facilitating the subsequent cyanide transfer and reductive elimination. Using this dual catalysis strategy, we cyanated aryl and alkenyl halides at room temperature in a highly benign manner (30 examples, 53-93% yields) by avoiding the use of air-sensitive ligands, Ni(0) processors, and hypertoxic cyanation reagents, while also not generating excess metal waste. Computational studies were also used to help understand the present transformation.

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Cyanation: a photochemical approach and applications in organic synthesis

Abstract: Photoredox chemistry has emerged as an efficient tool in catalyzing organic reactions as it utilizes light as an energy source without any external initiator or reagent. The cyanide group is...

Cited by 53 publications

References 245 publications

Photo and copper dual catalysis for allene syntheses from propargylic derivatives via one-electron process

Photo and copper dual catalysis for allene syntheses from propargylic derivatives via one-electron process

Ortho C−H Functionalization of 2‐Arylimidazo[1,2‐a]pyridines

Photoredox Catalysis Unlocks the Nickel-Catalyzed Cyanation of Aryl Halides under Benign Conditions

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