583-02-8Relevant articles and documents
CARBON-13 SUBSTITUENT CHEMICAL SHIFTS IN THE SIDE-CHAIN CARBONS OF AROMATIC SYSTEMS: THE IMPORTANCE OF Π-POLARIZATION IN DETERMINING CHEMICAL SHIFTS
Bromilow, John,Brownlee, Robert T. C.,Craik, David J.,Fiske, Peter R.,Rowe, Jeffrey E.,Sadek, Maruse
, p. 753 - 759 (1981)
13C substituent chemical shifts of the carbonyl sites in the side-chains of meta- and para-substituted benzenes of the type XC6H4COZ have been measured.Analysis of this data using the dual substituent parameter method shows that inductive effeccts are predominant.The reverse inductive contribution observed is explained in therms of a Π-polarization mechanism.Critical support for this mechanism is obtained from additional series where the carbonyl is complexed with Lewis acids.The concepts of 'extended' and 'localized' Π-polarization are discussed.
Copper-mediated simple and direct aerobic oxidative esterification of arylacetonitriles with alcohols/phenols
Dong, Jianyu,Chen, Xiuling,Ji, Fangyan,Liu, Lixin,Su, Lebin,Mo, Min,Tang, Jian-Sheng,Zhou, Yongbo
, (2020/10/20)
A simple and direct aerobic oxidative esterification reaction of arylacetonitriles with alcohols/phenols is achieved in the presence of a copper salt and molecular oxygen, which produces a broad range of aryl carboxylic acid esters in good to high yields. Copper salt plays multiple roles in the transformation, which allows the oxygenation of C-H bond, cleavage of inert C-C bond, and formation of C-O bond in one pot without the assistance of any of the acids, bases, ligands, and so on. The reaction provides a simple, direct, and efficient protocol towards functionalized esters, especially aryl benzoates, from readily available starting materials.
A Bifunctional Copper Catalyst Enables Ester Reduction with H2: Expanding the Reactivity Space of Nucleophilic Copper Hydrides
Kaicharla, Trinadh,Ngoc, Trung Tran,Teichert, Johannes F.,Tzaras, Dimitrios-Ioannis,Zimmermann, Birte M.
supporting information, p. 16865 - 16873 (2021/10/20)
Employing a bifunctional catalyst based on a copper(I)/NHC complex and a guanidine organocatalyst, catalytic ester reductions to alcohols with H2 as terminal reducing agent are facilitated. The approach taken here enables the simultaneous activation of esters through hydrogen bonding and formation of nucleophilic copper(I) hydrides from H2, resulting in a catalytic hydride transfer to esters. The reduction step is further facilitated by a proton shuttle mediated by the guanidinium subunit. This bifunctional approach to ester reductions for the first time shifts the reactivity of generally considered "soft"copper(I) hydrides to previously unreactive "hard"ester electrophiles and paves the way for a replacement of stoichiometric reducing agents by a catalyst and H2.
