154554-67-3Relevant articles and documents
Absolute Rate Constants for the Reactions of Some Carbon-Centered Radicals with 2,2,6,6-Tetramethylpiperidine-N-oxyl
Chateauneuf, J.,Lusztyk, J.,Ingold, K. U.
, p. 1629 - 1632 (1988)
A time-resolved, laser flash photolysis study of the reaction of a variety of carbon-centered radicals with Tempo (2,2,6,6-tetramethylpiperidine-N-oxyl) at room temperature is reported.Some of the radicals examined and the corresponding measured rate constants (M-1 s-1) are CH3(CH2)7CH2-radical, 1.2 * 109; (CH3)3C-radical, 7.6 * 108; C6H5CH2-radical, 4.9 * 108; C6H5C(CH3)2-radical, 1.2 * 108; (C6H5)2CCH3-radical, 4.6 * 107.Arrhenius parameters have also been determined for the n-nonyl and benzyl radicals.
On-demand acid-gated fluorescence switch-on in photo-generated nanospheres
Barner, Leonie,Barner-Kowollik, Christopher,Cavalli, Federica,Delafresnaye, Laura,Feist, Florian,Hooker, Jordan P.
, p. 4986 - 4989 (2020)
Herein, we introduce a fast, additive-free, ambient temperature photochemical approach - utilising the novel Diels-Alder cycloaddition of a photo-activeortho-methylbenzaldehyde (oMBA) with a terminal alkyne - for preparing functional acid-sensitive proflu
Selective electrochemical generation of benzylic radicals enabled by ferrocene-based electron-transfer mediators
Lennox, Alastair J.J.,Nutting, Jordan E.,Stahl, Shannon S.
, p. 356 - 361 (2018)
The generation and intermolecular functionalisation of carbon-centred radicals has broad potential synthetic utility. Herein, we show that benzylic radicals may be generated electrochemically from benzylboronate derivatives at low electrode potentials (ca. -0.3 V vs. Cp2Fe0/+) via single electron oxidation. Use of a catalytic quantity of a ferrocene-based electron-transfer mediator is crucial to achieve successful radical functionalisation and avoid undesirable side reactions arising from direct electrochemical oxidation or from the use of stoichiometric ferrocenium-based oxidants.
Electrochemical and Electrostatic Cleavage of Alkoxyamines
Zhang, Long,Laborda, Eduardo,Darwish, Nadim,Noble, Benjamin B.,Tyrell, Jason H.,Pluczyk, Sandra,Le Brun, Anton P.,Wallace, Gordon G.,Gonzalez, Joaquin,Coote, Michelle L.,Ciampi, Simone
, p. 766 - 774 (2018)
Alkoxyamines are heat-labile molecules, widely used as an in situ source of nitroxides in polymer and materials sciences. Here we show that the one-electron oxidation of an alkoxyamine leads to a cation radical intermediate that even at room temperature rapidly fragments, releasing a nitroxide and carbocation. Digital simulations of experimental voltammetry and current-time transients suggest that the unimolecular decomposition which yields the "unmasked" nitroxide (TEMPO) is exceedingly rapid and irreversible. High-level quantum computations indicate that the collapse of the alkoxyamine cation radical is likely to yield a neutral nitroxide radical and a secondary phenylethyl cation. However, this fragmentation is predicted to be slow and energetically very unfavorable. To attain qualitative agreement between the experimental kinetics and computational modeling for this fragmentation step, the explicit electrostatic environment within the double layer must be accounted for. Single-molecule break-junction experiments in a scanning tunneling microscope using solvent of low dielectric (STM-BJ technique) corroborate the role played by electrostatic forces on the lysis of the alkoxyamine C-ON bond. This work highlights the electrostatic aspects played by charged species in a chemical step that follows an electrochemical reaction, defines the magnitude of this catalytic effect by looking at an independent electrical technique in non-electrolyte systems (STM-BJ), and suggests a redox on/off switch to guide the cleavage of alkoxyamines at an electrified interface.
Enantioconvergent Cu-Catalyzed Radical C-N Coupling of Racemic Secondary Alkyl Halides to Access α-Chiral Primary Amines
Cheng, Jiang-Tao,Dong, Xiao-Yang,Gu, Qiang-Shuai,Li, Zhong-Liang,Liu, Juan,Liu, Xin-Yuan,Luan, Cheng,Wang, Fu-Li,Wang, Li-Lei,Yang, Ning-Yuan,Zhang, Yu-Feng
supporting information, p. 15413 - 15419 (2021/09/30)
α-Chiral alkyl primary amines are virtually universal synthetic precursors for all other α-chiral N-containing compounds ubiquitous in biological, pharmaceutical, and material sciences. The enantioselective amination of common alkyl halides with ammonia is appealing for potential rapid access to α-chiral primary amines, but has hitherto remained rare due to the multifaceted difficulties in using ammonia and the underdeveloped C(sp3)-N coupling. Here we demonstrate sulfoximines as excellent ammonia surrogates for enantioconvergent radical C-N coupling with diverse racemic secondary alkyl halides (>60 examples) by copper catalysis under mild thermal conditions. The reaction efficiently provides highly enantioenrichedN-alkyl sulfoximines (up to 99% yield and >99% ee) featuring secondary benzyl, propargyl, α-carbonyl alkyl, and α-cyano alkyl stereocenters. In addition, we have converted the masked α-chiral primary amines thus obtained to various synthetic building blocks, ligands, and drugs possessing α-chiral N-functionalities, such as carbamate, carboxylamide, secondary and tertiary amine, and oxazoline, with commonly seen α-substitution patterns. These results shine light on the potential of enantioconvergent radical cross-coupling as a general chiral carbon-heteroatom formation strategy.
Photoinduced Direct Addition of Alkylarenes to Imines
Ishida, Naoki,Kawasaki, Tairin,Murakami, Masahiro,Tomono, Ryota
supporting information, p. 1972 - 1974 (2022/01/12)
We herein report a direct addition reaction of simple alkylarenes to imines, which is driven by irradiation of the reactants with visible light in the presence of an iridium photoredox complex and a bromide anion. Phenethylamines including densely substituted derivatives are synthesized in an atom-economical fashion.
