2845-27-4Relevant academic research and scientific papers
Ruthenium-catalyzed intramolecular arene C(sp2)-H amidation for synthesis of 3,4-dihydroquinolin-2(1 H)-ones
Au, Chi-Ming,Ling, Cho-Hon,Sun, Wenlong,Yu, Wing-Yiu
supporting information, p. 3310 - 3314 (2021/05/29)
We report the [Ru(p-cymene)(l-proline)Cl] ([Ru1])-catalyzed cyclization of 1,4,2-dioxazol-5-ones to form dihydroquinoline-2-ones in excellent yields with excellent regioselectivity via a formal intramolecular arene C(sp2)-H amidation. The reactions of the 2- and 4-substituted aryl dioxazolones proceeds initially through spirolactamization via electrophilic amidation at the arene site, which is para or ortho to the substituent. A Hammett correlation study showed that the spirolactamization is likely to occur by electrophilic nitrenoid attack at the arene, which is characterized by a negative ρ value of -0.73.
Construction of enantioenriched 9H-Fluorene frameworks via a cascade reaction involving remote vinylogous dynamic kinetic resolution
Hu, Cui-Xia,Chen, Lin,Hu, Di,Song, Xue,Chen, Zhi-Chao,Du, Wei,Chen, Ying-Chun
supporting information, p. 8973 - 8977 (2020/11/30)
The benzylic C-H group of α,α-dicyanoolefins from 3-substituted 1-indanones could be significantly activated via transmission along the aromatic system, thus enabling dynamic kinetic resolution via a traditional reversible deprotonation- protonation process. Enantioenriched 9-substituted 9H-fluorene frameworks were finally constructed through an asymmetric vinylogous Michael addition to nitroolefins, followed by a cascade cyclization and oxidative aromatization process, under the catalysis of a chiral bifunctional thiourea-tertiary amine.
Identification of an Esterase Isolated Using Metagenomic Technology which Displays an Unusual Substrate Scope and its Characterisation as an Enantioselective Biocatalyst
Gavin, Declan P.,Murphy, Edel J.,Foley, Aoife M.,Castilla, Ignacio Abreu,Reen, F. Jerry,Woods, David F.,Collins, Stuart G.,O'Gara, Fergal,Maguire, Anita R.
, p. 2466 - 2474 (2019/03/11)
Evaluation of an esterase annotated as 26D isolated from a marine metagenomic library is described. Esterase 26D was found to have a unique substrate scope, including synthetic transformations which could not be readily effected in a synthetically useful manner using commercially available enzymes. Esterase 26D was more selective towards substrates which had larger, more sterically demanding substituents (i. e. iso-propyl or tert-butyl groups) on the β-carbon, which is in contrast to previously tested commercially available enzymes which displayed a preference for substrates with sterically less demanding substituents (e.g. methyl group) at the β-carbon. (Figure presented.).
Facile palladium-catalyzed hydrocarboxylation of olefins without external CO gas
Wang, Yang,Ren, Wenlong,Li, Jingfu,Wang, Haining,Shi, Yian
supporting information, p. 5960 - 5963 (2015/02/19)
An effective Pd-catalyzed hydrocarboxylation of olefins with phenyl formate and formic acid is described. A variety of carboxylic acids are obtained in good yields with high regioselectivities under operationally simple conditions without the use of toxic CO gas.
Influence of the position of the substituent on the efficiency of lipase-mediated resolutions of 3-aryl alkanoic acids
Deasy, Rebecca E.,Moody, Thomas S.,Maguire, Anita R.
, p. 1480 - 1487 (2013/12/04)
Hydrolase-catalysed kinetic resolutions to provide enantioenriched α-substituted 3-aryl alkanoic acids are described. (S)-2-Methyl-3- phenylpropanoic acid (S)-1a was prepared in 96% ee by Pseudomonas fluorescens catalysed ester hydrolysis, while, Candida antarctica lipase B (immob) resolved the α-ethyl substituted 3-arylalkanoic acid (R)-1b in 82% ee. The influence of the position of the substituent relative to the ester site on the efficiency and enantioselectivity of the biotransformation is also explored; the same lipases were found to resolve both the α- and β-substituted alkanoic acids. Furthermore, the steric effect of substituents at the C2 stereogenic centre relative to that for their C3 substituted counterparts on the efficiency and stereoselectivity is discussed.
The studies on chemoenzymatic synthesis of Femoxetine
Brodzka, Anna,Koszelewski, Dominik,Ostaszewski, Ryszard
, p. 96 - 101 (2012/09/25)
The studies on enzymatic kinetic resolution of 3-phenyl-4-pentenoic acid esters were performed. The obtained results demonstrated that the careful choice of biocatalyst and a reaction type are very important for successful enzymatic kinetic resolution. Ki
Lipase catalysed kinetic resolutions of 3-aryl alkanoic acids
Deasy, Rebecca E.,Brossat, Maude,Moody, Thomas S.,Maguire, Anita R.
experimental part, p. 47 - 61 (2011/04/18)
Hydrolase catalysed kinetic resolutions leading to a series of 3-aryl alkanoic acids (≥94% ee) are described. Hydrolysis of the ethyl esters with a series of hydrolases was undertaken to identify biocatalysts that yield the corresponding acids with excellent enantiopurity in each case. Steric and electronic effects on the efficiency and enantioselectivity of the biocatalytic transformation were also explored.
Copper-catalyzed enantioselective conjugate addition of dialkylzinc reagents to α′-oxy enones
Garcia, Jesus M.,Gonzalez, Alberto,Kardak, Bharat G.,Odriozola, Jose M.,Oiarbide, Mikel,Razkin, Jesus,Palomo, Claudio
supporting information; experimental part, p. 8768 - 8771 (2009/10/01)
The copper-catalyzed enantioselective conjugate addition of dialkylzinc reagents to α'-oxy enones was investigated. Cu(OTf)2, ligand, and toluene were placed in a flame-dried Schlenk tube. the resulting mixture was stirred at room temperature f
An unusual β-vinyl effect leading to high efficiency and enantioselectivity of the amidase, nitrile biotransformations for the preparation of enantiopure 3-arylpent-4-enoic acids and amides and their applications in synthesis
Gao, Ming,Wang, De-Xian,Zheng, Qi-Yu,Wang, Mei-Xiang
, p. 9532 - 9535 (2007/10/03)
(Chemical Equation Presented) Biotransformations of 3-arylpent-4- enenitriles catalyzed by Rhodococcus erythropolis AJ270, a nitrile hydratase/amidase-containing microbial whole-cell catalyst were studied, and an unusual β-vinyl effect of the substrate on
(S,S)-(+)-pseudoephedrine as chiral auxiliary in asymmetric conjugate addition and tandem conjugate addition/α-alkylation reactions
Reyes, Efraim,Vicario, Jose L.,Carrillo, Luisa,Badia, Dolores,Uria, Uxue,Iza, Ainara
, p. 7763 - 7772 (2007/10/03)
(Chemical Equation Presented) Organolithium reagents undergo highly regio- and diastereoselective 1,4-addition to (S,S)-(+)-pseudoephedrine enamides furnishing the corresponding β-alkyl-substituted adducts in excellent yields and diastereoselectivities. In addition, the intermediate lithium enolates generated after the conjugate addition step undergo a highly diastereoselective alkylation reaction, furnishing α,β-dialkyl- substituted amides in high yields. The obtained adducts have been converted into chiral nonracemic β-alkyl- and α,β-dialkyl-substituted carboxylic acids and γ-alkyl- and β,γ-dialkyl-substituted alcohols using very simple and high-yielding procedures.
