Energietransfervermittelte intermolekulare Carboiminylierung von Alkenen durch den “Persistent Radical Effect”

Abstract

Eine intermolekulare vicinale Zwei-Komponenten-Carboiminylierung von Alkenen wurded urch Energietransferkatalyse erreicht. Oximester von Alkylcarbonsäuren werden als bifunktionelle Reagenzien zur Erzeugung von Alkyl-und Iminylradikalen verwendet. Die Addition des Alkylradikals an ein Alken erzeugt dabei ein transientes Radikal, das anschließend selektive Radikal-Radikal-Kupplung mit dem persistenten Iminylradikal eingeht. Durch anschließende Hydrolyse des Imins ermçglicht diese Methode direkten Zugang zu primären aliphatischen Aminen sowie a-Aminosäuren.

Regioselective Access to Vicinal Diamines by Metal‐Free Photosensitized Amidylimination of Alkenes with Oxime Esters

“…To validate our hypothesis, we set out to prepare the designed diamination reagent by starting from commercially available tert ‐butyl hydroxycarbamate and methyl 2‐bromo‐2‐methylpropanoate. Pleasingly, the expected oxime ester 1 a was facilely synthesized through a three‐step process in 67 % overall yield [9g, 14] . Next, oxime ester 1 a and 4‐methoxystyrene ( 2 a ) were employed as model substrates to evaluate their reactivity.…”

Recent Uses of Photogenerated Oxygen-Centered Radicals in Intermolecular C–O Bond Formation

“…One way of circumventing this issue and of reaching full atom economy was provided by Yuan, Bao and Huo in 2021. 9 They were inspired by the works of Cho 10 and Glorius, 11 who used aliphatic oxime esters as sources of both iminyl radical and carbon-centered radical (obtained after decarboxylation of the corresponding acyloxy radical) via a homolytic N–O bond cleavage induced by photosensitized energy transfer (EnT). In this new study, the same energy transfer pathway was used to generate both the aroyloxy radical and the iminyl radical from the corresponding aryl oxime ester 6 (R = Aryl, Scheme 4 ).…”

Decarboxylative, Radical C–C Bond Formation with Alkyl or Aryl Carboxylic Acids: Recent Advances

“…29 Although less developed than many of the above strategies, the latter approach does provide one of the few effective means of generating aryl radicals from benzoic acids, 29c and the iminyl radical 20 co-generated with radical 17 can be used productively to form C–N bonds alongside new C–C bonds. 29a b…”