نتایج جستجو برای: stereoselectively

تعداد نتایج: 274  

Journal: :Synlett 2021

Abstract Metal-catalyzed alkylation of 1,1-dihalovinyl moiety commonly suffers from both a lack stereoselectivity and the overreaction leading to dialkylation product. The methodology described herein features new pathway alkylate stereoselectively β,β-dichlorostyryl substrates provide Z-trisubstituted olefin only with fair good yields. This cross-coupling reaction bears on smooth photoinduced ...

Journal: :Synthesis 2021

Abstract A pentasaccharide repeating unit corresponding to the cell wall O-antigen of Salmonella enterica O55 containing a rare sugar, 3-acetamido-3-deoxy-d-fucose has been synthesized as its p-methoxyphenyl glycoside using sequential stereoselective glycosylation strategy. suitably functionalized 3-azido-3-deoxy-d-fucose thioglycoside derivative was prepared in very good yield and used reactio...

Journal: :iranian biomedical journal 0
غلام رضا اصغری gholamreza asghari george brian lockwood

the enzymatic potential of the cultured plant cells can be employed for bioconversion purposes. plant enzymes are able to catalyze regio- and stereo-specific reactions, and therefore can be applied for the production of desired substances. the biotransformation of foreign substrates with suspension cells of peganum harmala was tested with (±) phenylethyl propionate. the callus cultures of pegan...

2012
Ellen Klegraf Horst Kunz

The stereoselective synthesis of 3-substituted and 3,4-disubstituted piperidine and piperidin-2-one derivatives was achieved starting from 2-pyridone. After N-galactosylation and subsequent O-silylation, nucleophilic addition of organometallic reagents proceeded with high regioand stereoselectivity at 4-position. Substituents at position 3 were stereoselectively introduced by reaction of electr...

Journal: :Chemical communications 2012
Seda Cantekin Yoko Nakano Jeffrey C Everts Paul van der Schoot E W Meijer Anja R A Palmans

Small changes in the alkane solvent structure in combination with temperature effects lead to four different conformations of stereoselectively deuterated benzene-1,3,5-tricarboxamides in the aggregated state, affecting the expression of the supramolecular chirality and highlighting the role of the solvent structure in self-assembly processes.

Journal: :Chemical communications 2011
Jiechao Xu Jiamei Wei Linglin Bian Jiaping Zhang Jie Chen Hongmei Deng Xiaoyu Wu Hui Zhang Weiguo Cao

cis-2,3-Dihydro-4-perfluoroalkyl-1H-1,5-benzodiazepines were stereoselectively synthesized using a one-pot, catalyst-free, three-component reaction. This novel, efficient and convenient approach was used to synthesize 22 related products in moderate to excellent yields, demonstrating the scope and potential economic impact of the reaction.

Journal: :Chemical communications 2015
Marek Knor Hong-Ying Gao Saeed Amirjalayer Armido Studer Hongjun Gao Shixuan Du Harald Fuchs

Polymerization of 1,4-diaminonaphthalene on various Cu substrates resulting in stereoselectively well-defined metal-organic coordination polymers is reported. By using different crystallographic planes (111), (110) and (100) of a Cu substrate the structure of the resulting coordination polymer was controlled.

Journal: :Chemical & pharmaceutical bulletin 2000
A Wada Y Nomoto K Tano E Yamashita M Ito

Palladium catalyzed cross coupling reactions of a vinyl triflate intermediate and various alkenyl stannanes afforded trisubstituted Z-olefins stereoselectively in high yields. These olefins were then converted to the corresponding 9Z-retinoic acids via Horner-Emmons reaction and subsequent basic hydrolysis in excellent yields.

2016
Ruth Dorel Antonio M. Echavarren

The [3,5,5,7] tetracyclic skeleton of echinopines has been stereoselectively accessed through a gold(I)-catalyzed alkoxycyclization of cyclopropyl-tethered 1,6-enynes. The key bicyclo[4.2.1]nonane core of the enyne precursors was readily assembled by means of a Co-catalyzed [6 + 2] cycloaddition. Furthermore, the attempted alkoxycyclization of 1,5-enyne substrates revealed an uncovered cyclopro...

Journal: :Bioscience, biotechnology, and biochemistry 2008
Tomofumi Nakato Ryosuke Tago Koichi Akiyama Masafumi Maruyama Takuya Sugahara Taro Kishida Satoshi Yamauchi

Tetra-substituted tetrahydrofuran compounds were stereoselectively prepared from benzylic hemiacetal in the neutral condition by employing the simple reagent, H(2), and a Pd catalyst. The stereoselective conversion of benzylic hemiacetal to two different stereoisomers of the tetrasubstituted tetrahydrofuran compound was observed. One of these tetrahydrofuran compounds was converted to the virga...

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