نتایج جستجو برای: enantioselectivity

تعداد نتایج: 1696  

Journal: :Chemical communications 2010
Masaharu Sugiura Mirai Tokudomi Makoto Nakajima

We have found that O-monoacyltartaric acids catalyze asymmetric conjugate addition of boronic acids to enones with good enantioselectivity, and the 3,5-di(tert-butyl)benzoyl group provides the best results among the acyl groups examined.

Journal: :Chemical communications 2012
Shohei Aoki Shunsuke Kotani Masaharu Sugiura Makoto Nakajima

Trichlorosilyl triflate-promoted directed cross-aldol reaction between ketones in the presence of a chiral phosphine oxide as an organocatalyst is described. This is the first enantioselective cross-aldol reaction between simple ketones with good enantioselectivity.

Journal: :Chemical communications 2013
Takahiro Nishimura Yusuke Ebe Hiroto Fujimoto Tamio Hayashi

Asymmetric addition of arylboronates to aryl-substituted cyclic ketimines proceeded in the presence of a rhodium catalyst coordinated with a chiral diene ligand to give high yields of sulfamidates and sulfamides with high enantioselectivity (up to 99% ee).

Journal: :Chemical communications 2012
Masashi Shibata Masahiro Ikeda Kazuki Motoyama Yoshihiro Miyake Yoshiaki Nishibayashi

Enantioselective alkylation of β-keto phosphonates with diaryl methanols in the presence of catalytic amounts of copper(II) trifluoromethanesulfonate and an optically active ligand gives the corresponding alkylated products in good to high yields with a high enantioselectivity.

Journal: :Organic letters 2005
You-Qing Wang Sheng-Mei Lu Yong-Gui Zhou

[reaction: see text]. A novel catalytic system for asymmetric hydrogenation of functionalized ketones has been developed using a Pd/bisphosphine complex as the catalyst in 2,2,2-trifluoroethanol. The reaction exhibits high enantioselectivity, and up to 92.2% ee was obtained.

2013
Yan-Chao Shi Rong-Fei Yang De-Wei Gao Shu-Li You

When Boc-L-Val-OH was used as a ligand for the enantioselective Pd(II)-catalyzed annulation of N,N-substituted aminomethyl ferrocene derivatives with diarylethynes, ferrocenes with planar chirality could be achieved with excellent enantioselectivity (up to 99% ee).

Journal: :Catalysts 2022

The introduction of nitrogen to carbonyl groups is considered both challenging and highly desirable by those who work in the field organic synthesis. In this study, a diphenylethylenediamine-derived catalyst demonstrating N-selectivity was designed using quantum calculation for nitroso aldol reaction. reductive monoalkylation (R,R)-(+)-1,2-diphenylethylenediamine afforded an chiral diamine high...

2016
Davide Brenna Elisabetta Massolo Alessandra Puglisi Sergio Rossi Giuseppe Celentano Maurizio Benaglia Vito Capriati

Different deep eutectic solvent (DES) mixtures were studied as reaction media for the continuous synthesis of enantiomerically enriched products by testing different experimental set-ups. L-Proline-catalysed cross-aldol reactions were efficiently performed in continuo, with high yield (99%), anti-stereoselectivity, and enantioselectivity (up to 97% ee). Moreover, using two different DES mixture...

Journal: :Journal of the American Chemical Society 2013
Elad Gross Jack H Liu Selim Alayoglu Matthew A Marcus Sirine C Fakra F Dean Toste Gabor A Somorjai

Research to develop highly versatile, chiral, heterogeneous catalysts for asymmetric organic transformations, without quenching the catalytic reactivity, has met with limited success. While chiral supramolecular structures, connected by weak bonds, are highly active for homogeneous asymmetric catalysis, their application in heterogeneous catalysis is rare. In this work, asymmetric catalyst was ...

Journal: :Molecules 2013
Zecheng Yang Xuedun Niu Xuedong Fang Ge Chen Hong Zhang Hong Yue Lei Wang Dantong Zhao Zhi Wang

Enantioselective esterification of ibuprofen has been successfully carried out in an organic solvent catalyzed by recombinant APE 1547 (a thermophilic esterase from the archaeon Aeropyrum pernix K1). Here we used microwave irradiation (MW) as the mode of heating to improve the enzyme performance. Under the optimum conditions, the enzyme activity of APE 1547 was 4.16 μmol/mg/h and the enantiosel...

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