نتایج جستجو برای: enantioselectivity

تعداد نتایج: 1696  

2013
Qiang Wei Ya-Yi Wang Yu-Liu Du Liu-Zhu Gong

A chiral phosphoric acid-catalyzed selenofunctionalization of tryptamine derivatives provides access to 3a-(phenylselenyl)-1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole derivatives in high yields and with synthetically useful levels of enantioselectivity (up to 89% ee).

Journal: :Organic & biomolecular chemistry 2012
Abhijnan Ray Choudhury Santanu Mukherjee

The first organocatalytic enantioselective direct vinylogous Michael reaction of α,β-unsaturated γ-butyrolactam to nitroolefins is developed using cinchona alkaloids as the catalysts. Both product enantiomers are accessible with moderate to good enantioselectivity.

Journal: :Applied and environmental microbiology 2008
Roi Feingersch Janna Shainsky Thomas K Wood Ayelet Fishman

Enantiopure sulfoxides are valuable asymmetric starting materials and are important chiral auxiliaries in organic synthesis. Toluene monooxygenases (TMOs) have been shown previously to catalyze regioselective hydroxylation of substituted benzenes and phenols. Here we show that TMOs are also capable of performing enantioselective oxidation reactions of aromatic sulfides. Mutagenesis of position ...

Journal: :Antiviral chemistry & chemotherapy 2000
Y L Qiu F Geiser T Kira E Gullen Y C Cheng R G Ptak J M Breitenbach J C Drach C B Hartline E R Kern J Zemlicka

A series of R and S enantiomers of 2-aminopurine methylenecyclopropane analogues of nucleosides was synthesized. Two diastereoisomeric lipophilic phosphate prodrugs derived from R and S enantiomers of 2,6-diaminopurine analogue were also prepared. Enantioselectivity (diastereoselectivity in case of prodrugs) of in vitro antiviral effects was investigated with human and murine cytomegalovirus (H...

Journal: :Natural sciences 2023

Proteins are useful chiral selectors. In order to understand the recognition mechanism and discrimination, binding of (R)- (S)-enantiomers a series designed amino alcohol inhibitors based on propranolol cellobiohydrolase Cel7A (Trichoderma reesei) has been studied more closely. X-ray crystal structures were determined protein complex with strongest analogue. The combination structural data, the...

Journal: :Catalysts 2022

Michael addition is an important reaction because it can be used to synthesize a wide range of natural products or complex compounds that exhibit biological activities. In this study, mirror image aldehyde and α,β-unsaturated nitroalkene were reacted in the presence (R,R)-1,2-diphenylethylenediamine (DPEN). Herein, thiourea was introduced as organic catalyst, selective carried out. The primary ...

Journal: :Chemistry 2004
Bernd Goldfuss Thomas Löschmann Frank Rominger

Modular fenchyl phosphinites (FENOPs) containing different aryl units-phenyl (1), 2-anisyl (2), or 2-pyridyl (3)-are efficiently accessible from (-)-fenchone. For comparison of the influence of the different aryl units on enantioselectivities and reactivities, these FENOPs were employed in Pd-catalyzed allylic alkylations. The strongly chelating character of P,N-bidentate 3 is apparent from X-r...

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