16417-06-4Relevant academic research and scientific papers
Photochemical generation of acyl and carbamoyl radicals using a nucleophilic organic catalyst: Applications and mechanism thereof
Balletti, Matteo,De Pedro Beato, Eduardo,Mazzarella, Daniele,Melchiorre, Paolo
, p. 6312 - 6324 (2020/08/24)
We detail a strategy that uses a commercially available nucleophilic organic catalyst to generate acyl and carbamoyl radicals upon activation of the corresponding chlorides and anhydrides via a nucleophilic acyl substitution path. The resulting nucleophilic radicals are then intercepted by a variety of electron-poor olefins in a Giese-type addition process. The chemistry requires low-energy photons (blue LEDs) to activate acyl and carbamoyl radical precursors, which, due to their high reduction potential, are not readily prone to redox-based activation mechanisms. To elucidate the key mechanistic aspects of this catalytic photochemical radical generation strategy, we used a combination of transient absorption spectroscopy investigations, electrochemical studies, quantum yield measurements, and the characterization of key intermediates. We identified a variety of off-the-cycle intermediates that engage in a light-regulated equilibrium with reactive radicals. These regulated equilibriums cooperate to control the overall concentrations of the radicals, contributing to the efficiency of the overall catalytic process and facilitating the turnover of the catalyst. This journal is
Electronic effect of substituents and mechanism on the formation of diethyl 3-oxo-3-arylpropyl phosphonates
Yu, Jen-Wen,Chong, Chien-Keun,Huang, Steve K.
, p. 235 - 242 (2007/10/03)
The reaction of aryl β-chloroethyl ketones with triethyl phosphite to give γ-ketophosphonates was studied kinetically. This reaction follows a second order overall and involves a carbonyl group-assisted (CGA) initializing step, followed by a stereoselective pathway to γ-ketophosphonates. A linear Hammett plot reveals that the p value is 1.51 (r=0.994), and the transition state is accelerated by the para-halogen on the phenyl group. The results confirm the two-stage mechanism and rule out an SN2 mechanism being responsible for the formation of diethyl 3-oxo-3-arylpropyl phosphonates 3.
