577-56-0Relevant articles and documents
Ground and excited state hydrogen atom transfer reactions and cyclization of 2-acetylbenzoic acid
Santos,Vargas,Moreno,Manzano,Lluch,Douhal
, p. 9331 - 9341 (2004)
We present experimental and theoretical studies of the ring-chain tautomerism (H-atom transfer and cyclization) for 2-acetylbenzoic acid at both ground and electronically first excited states. 1H and 13C NMR studies in solution confirm the existence of equilibrium between the open and ring structures at the ground state, with the ring one being dominant (~90%). Temperature-dependent 1H NMR experiments allowed obtaining the thermodynamic and kinetic parameters at the coalescence temperature (380 K). Fluorescence measurements disclose the involvement of highly efficient nonradiative processes in agreement with the theoretical data. Electronic calculations for the ground state give additional information on the different conformers of the open tautomer. In agreement with the experiment the most stable structure is of the closed ring tautomer, and it is obtained after additional internal rotations of the -COOH and -CO(CH3) fragments. Intrinsic reaction coordinate calculations indicate that the ring formation/breaking and the H-atom transfer are taking place in a concerted but not synchronous manner. At S1 the most stable form is the open one, for which different conformers are also found. The influence of the solvent is also accounted for through a model that considers the solvent as a continuum at both the ground and excited electronic states. No major differences were observed when comparing both gas and condensed phase results, so calculations of the isolated molecule should give a picture of the reaction which is experimentally observed in solution.
Synthesis of dibenzocycloketones by acyl radical cyclization from aromatic carboxylic acids using methylene blue as a photocatalyst
Jiang, Hongshuo,Mao, Guijie,Wu, Hongfeng,An, Qi,Zuo, Minghui,Guo, Weihao,Xu, Chunzhao,Sun, Zhizhong,Chu, Wenyi
supporting information, p. 5368 - 5373 (2019/10/11)
An efficient intramolecular radical cyclization reaction via photoredox catalysis was developed for the synthesis of dibenzocycloketone derivatives using methylene blue as a photosensitizer. This strategy could be widely used to synthesize large heterocycles due to the unique reactivity of phosphoranyl radicals formed by a polar/SET crossover between an aromatic carboxylic acid and a phosphine radical cation. Attractive features of this process include generation of an acyl radical by an inexpensive and metal-free photocatalyst, which effectively undergoes a cyclization process.
Aerobic Photooxidative Synthesis of β-Alkoxy Monohydroperoxides Using an Organo Photoredox Catalyst Controlled by a Base
Asano, Yuya,Nagasawa, Yoshitomo,Yamaguchi, Eiji,Itoh, Akichika
supporting information, p. 409 - 412 (2018/02/21)
Transition-metal-free synthesis of β-alkoxy monohydroperoxides via aerobic photooxidation using an acridinium photocatalyst was developed. This method enables the synthesis of some novel hydroperoxides. The peroxide source is molecular oxygen, which is cost-effective and atomically efficient. Magnesium oxide plays an important role as a base in the catalytic system.