Reactions of the carbonate radical with aliphatic amines

Elango, T. P.; Ramakrishnan, V.; Vancheesan, S.; Kuriacose, J. C.

doi:10.1016/s0040-4020(01)91404-8

Cited by 29 publications

(22 citation statements)

References 19 publications

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“…The reactions of C0;-with a number of aliphatic amines have been investigated previously [28]. Whereas the reactions of the primary amines appeared to proceed primarily by hydrogen abstraction, the reactions with the tertiary amines, such as triethylamine, were suggested to take place by electron transfer.…”

Section: Discussionmentioning

confidence: 99%

Temperature dependence of the rate constants for reactions of the carbonate radical with organic and inorganic reductants

Huie

Shoute

Neta

1991

Int J of Chemical Kinetics

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Rate constants have been measured by pulse radiolysis for the reactions of the carbonate radical, COa'-, with a number of organic and inorganic reactants as a function of temperature, generally over the range 5 to 80°C. The reactants include the substitution-inert cyano complexes of Fe", Mo", and W", the simple inorganic anions SO$-, ClOz-, NOz-, I-, and SCN-, several phenolates, ascorbate, tryptophan, cysteine, cystine, methionine, triethylamine, and ally1 alcohol. The measured rate constants ranged from less than lo5 to 3 x lo9 M-' s-', the activation energies ranged from -11.4 to 18.8 k J mol-', and the pre-exponential factors ranged from log A = 6.4 to 10.7. The activation energies for the metal complexes and inorganic anions generally decrease with increasing driving force for the reaction, as expected for an outer sphere electron transfer. For highly exothermic reactions, however, the activation energy appears to increase, probably reflecting the temperature dependence of diffusion. For many of the organic reactants, the activation energies were low and independent of driving force, suggesting that the oxidation is via an inner sphere mechanism.

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Section: Discussionmentioning

confidence: 99%

Temperature dependence of the rate constants for reactions of the carbonate radical with organic and inorganic reductants

Huie

Shoute

Neta

1991

Int J of Chemical Kinetics

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“…3 However, a widespread application of ketyl radicals in synthesis has been hindered by (i) the highly negative reduction potential 4 of aldehydes ( E 1/2 red = −1.93 V vs. SCE for benzaldehyde), 5 ketones ( E 1/2 red = −2.11 V vs. SCE for acetophenone), 5 and imines ( E 1/2 red = −1.91 V vs. SCE for N -benzylideneaniline) 5 (Scheme 1) and (ii) the requirement to employ toxic, air- and moisture-sensitive reducing agents, and harsh reaction conditions to generate the ketyl and α-aminoalkyl anion radical intermediates. Accordingly, early examples of reductive coupling reactions between carbonyl derivatives and alkenes/alkynes were performed using very strong reductants such as alkali 6 and alkali earth 7 metals, tin, 8-13 zinc, 14, 15 titanium, 16 and samarium reagents, 17-22 as well as under electrochemical 23-26 and photochemical 27-32 conditions. Due to the severe drawbacks of these strategies, such as the requirement for a strong reductant and generation of a stoichiometric amount of organometallic by-products, there has been a growing demand for development of new methods to access ketyl and α-aminoalkyl anion radicals under mild and eco-compatible reaction conditions.…”

Section: Introductionmentioning

confidence: 99%

Recent developments in transition-metal photoredox-catalysed reactions of carbonyl derivatives

2017

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Single-electron reduction of C=O and C=N bonds of aldehydes, ketones, and imines results in the formation of ketyl and α-aminoalkyl anion radicals, respectively. These reactive intermediates are characterized by an altered electronic character with respect to their parent molecules and undergo a diverse range of synthetically useful transformations, which are not available to even-electron species. This Review summarizes the reactions of ketyl and α-aminyl radicals generated from carbonyl derivatives under transition-metal photoredox-catalysed conditions. We primarily focus on recent developments in the field, as well as give a brief overview of catalytic enantioselective transformations that provide means to achieve precise stereocontrol over the reactivity of ion radicals.

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“…[2] Like the hydroxyl radical, the carbonate radical can attack organic substances via electron-transfer or H-atom abstraction mechanisms. For kinetic studies, a spectroscopic system is usually combined with flash photolysis [7][8][9][10][11][12] or pulse radiolysis. [3] The carbonate radical anion is conveniently generated by photolysis or radiolysis of carbonate solutions or by reacting peroxynitrite with carbon dioxide, vide infra.…”

Section: Introductionmentioning

confidence: 99%

Reactivity of the Carbonate Radical Anion Towards Carbohydrate and Lignin Model Compounds

Stenman

Carlsson

Jönsson

et al. 2003

Journal of Wood Chemistry and Technology

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Reactions of the carbonate radical with aliphatic amines

Cited by 29 publications

References 19 publications

Temperature dependence of the rate constants for reactions of the carbonate radical with organic and inorganic reductants

Temperature dependence of the rate constants for reactions of the carbonate radical with organic and inorganic reductants

Recent developments in transition-metal photoredox-catalysed reactions of carbonyl derivatives

Reactivity of the Carbonate Radical Anion Towards Carbohydrate and Lignin Model Compounds

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