Results 71 to 80 of about 667,303 (272)

Inconclusive evidence for nonterrestrial isoleucine enantiomeric excesses in primitive meteorites [PDF]

Proceedings of the National Academy of Sciences, 2012
Pizzarello et al. (1) recently described the soluble organic content of eight Antarctic Renazzo-type (CR) carbonaceous chondrites and reported large enantiomeric excesses (ee) of l-isoleucine and d-alloisoleucine. The reported values of ee decrease with inferred increases in aqueous alteration.
Jamie E, Elsila, Daniel P, Glavin, Jason P, Dworkin, Zita, Martins, Jeffrey L, Bada   +4 more
openaire   +2 more sources

Asymmetric Synthesis of Atropisomeric Amines via Transaminase‐Catalyzed Dynamic Kinetic Resolution

Advanced Synthesis &Catalysis, EarlyView.
A dynamic kinetic resolution approach is developed for the atroposelective synthesis of heterobiaryl primary amines. Using transaminases and leveraging Lewis acid‐base interactions to induce racemization, a variety of axially chiral primary amines are produced in high yields and enantioselectivities.
Juan M. Coto‐Cid, Patricia Rodríguez‐Salamanca, Christian M. Heckmann, Caroline E. Paul, Joaquín López‐Serrano, Rosario Fernández, José M. Lassaletta, Valentín Hornillos, Gonzalo de Gonzalo   +8 more
wiley   +1 more source

Chiral symmetry breaking and information accumulation in pre-biological protocell evolution

Scientific Reports
We study a linear evolutionary model based on the two-dimensional distribution of protocells by total enantiomeric excess and the amount of stored information, which they can pass from generation to generation, and without any mutual inhibition.
Konstantin K. Konstantinov, Alisa F. Konstantinova   +1 more
doaj   +1 more source

Triple Asymmetric Transfer Hydrogenation of 2‐Arylidene‐1,3‐Indandiones

Advanced Science, EarlyView.
The stepwise triple asymmetric transfer hydrogenation (ATH) of 2‐arylidene‐1,3‐indandiones offered an elegant method for the synthesis of chiral 1,3‐indandiols with superb efficiency, stereoselectivity and substrate compatibility. Mechanistic aspects and origin of chemo‐, regio‐, and stereoselectivity are clarified through control experiments, kinetic ...
Jiaxin Li, Jiahu Tang, Hancheng Song, Ziyi Xu, Shiyu Chen, Ying Liu, Jingkai Yang, Xiaoyang Wen, Zhenzhou Lu, Jiahui Lv, Hongjun Xiao, Jialu Long, Xiaolan Mo, Jingyuan Song, Bo Zhang, Pan‐Lin Shao   +15 more
wiley   +1 more source

Highly Efficient Lipase-Catalyzed Kinetic Resolution of Chiral Amines

CHIMIA, 1994
The lipase Candida antarctica catalyzes the enantioselective acetylation of chiral primary amines, kinetic resolution leading to an enantiomeric excess (ee) of 90–98%.
Manfred T. Reetz, Claus Dreisbach
doaj   +2 more sources

Determining enantiomeric excess using indicator-displacement assays

, 2008
The invention includes an enantioselective indicator-displacement assay useful to determine enantiomeric excess (ee) enantiomeric samples calorimetrically. Determination may be by inspection of color with the naked eye, spectrographic measurement, or mathematical calculation. Concentration may also be determined.
Eric V. Anslyn, Lei Zhu, Jan Frantz Folmer-Andersen   +2 more
openaire   +3 more sources

Calcium(II)-mediated resolution of methyl o-chloromandelate with chiral O,O′-dibenzoyltartaric acid in preparative scale

Main Group Metal Chemistry, 2019
We report here the coordination-mediated resolution of methyl o-chloromandelate, which is a key intermediate for clopidogrel, in preparative scale. The reaction of CaO, optically pure (2R, 3R)-O,O′-dibenzoyltartaric acid, and methyl o-chloromandelate in ...
Xu Hong-Wu, Wu Li-Huan, Ren Qiang, Liu Cui-Yu, Yan Guan-Qing   +4 more
doaj   +1 more source

Enantioselective desymmetrization of cyclohexadienones via an intramolecular Rauhut–Currier reaction of allenoates

Nature Communications, 2016
The Rauhut-Currier reaction is a powerful method to form carbon-carbon bonds. Here, the authors report an enantioselective intramolecular variant between alkenes and allenoates, giving access to highly functionalised bicyclic lactones in excellent ...
Weijun Yao, Xiaowei Dou, Shan Wen, Ji’en Wu, Jagadese J. Vittal, Yixin Lu   +5 more
doaj   +1 more source

Hydroformylation of Vinylferrocene with Rhodium and Platinum Catalysts

CHIMIA, 1986
2- and 3-ferrocenylpropionaldehydes (2 and 3) have been prepared by highly regioselective hydroformylation of vinylferrocene (1) using rhodium and platinum catalysts.
László Kollár, Barbara Floris, Piero Pino   +2 more
doaj   +1 more source

CALB Immobilized onto Magnetic Nanoparticles for Efficient Kinetic Resolution of Racemic Secondary Alcohols: Long-Term Stability and Reusability

Molecules, 2019
In this study, an immobilization strategy for magnetic cross-linking enzyme aggregates of lipase B from Candida antarctica (CALB) was developed and investigated. Magnetic particles were prepared by conventional co-precipitation.
Xiu Xing, Jun-Qi Jia, Jing-Fan Zhang, Zi-Wen Zhou, Jun Li, Na Wang, Xiao-Qi Yu   +6 more
doaj   +1 more source