4346-18-3Relevant articles and documents
Cobalt-Catalyzed Radical Hydroamination of Alkenes with N-Fluorobenzenesulfonimides
Lv, Guowei,Meng, Qi,Qin, Tao,Xiong, Tao,Zhang, Ge,Zhang, Qian
supporting information, p. 25949 - 25957 (2021/11/01)
An efficient and general radical hydroamination of alkenes using Co(salen) as catalyst, N-fluorobenzenesulfonimide (NFSI) and its analogues as both nitrogen source and oxidant was successfully disclosed. A variety of alkenes, including aliphatic alkenes, styrenes, α, β-unsaturated esters, amides, acids, as well as enones, were all compatible to provide desired amination products. Mechanistic experiments suggest that the reaction underwent a metal-hydride-mediated hydrogen atom transfer (HAT) with alkene, followed by a pivotal catalyst controlled SN2-like pathway between in situ generated organocobalt(IV) species and nitrogen-based nucleophiles. Moreover, by virtue of modified chiral cobalt(II)-salen catalyst, an unprecedented asymmetric version was also achieved with good to excellent level of enantiocontrol. This novel asymmetric radical C?N bond construction opens a new door for the challenging asymmetric radical hydrofunctionalization.
Activity and specificity studies of the new thermostable esterase EstDZ2
Myrtollari, Kamela,Katsoulakis, Nikolaos,Zarafeta, Dimitra,Pavlidis, Ioannis V.,Skretas, Georgios,Smonou, Ioulia
, (2020/09/16)
In this paper, we study the activity and specificity of EstDZ2, a new thermostable carboxyl esterase of unknown function, which was isolated from a metagenome library from a Russian hot spring. The biocatalytic reaction employing EstDZ2 proved to be an efficient method for the hydrolysis of aryl p-, o- or m-substituted esters of butyric acid and esters of secondary alcohols. Docking studies revealed structural features of the enzyme that led to activity differences among the different substrates.
Hydroxy-Directed Amidation of Carboxylic Acid Esters Using a Tantalum Alkoxide Catalyst
Tsuji, Hiroaki,Yamamoto, Hisashi
supporting information, p. 14218 - 14221 (2016/11/13)
We describe herein a new strategy for the chemoselective synthesis of amides by using a metal-catalyzed hydroxy-directed reaction. A hydroxy group located at the β-position of an ester group promoted the activation of a carbonyl group with a tantalum alkoxide catalyst followed by amidation reactions, leading to a wide variety of β-hydroxyamides with excellent chemeselectivity. The chemoselective amidation strategy can be extended to the catalytic synthesis of dipeptide derivatives, which remains challenging research subjects in modern organic synthesis.
