نتایج جستجو برای: chiral spiro oxindolopyrrolidines

تعداد نتایج: 39527  

Journal: :Chemistry, an Asian journal 2009
Kuiling Ding Zhaobin Han Zheng Wang

This Focus Review highlights the exciting results obtained in the area of asymmetric catalysis using spirobiindane- or spirobifluorene-based chiral ligands. The spiro, mono, and bidentate ligands have been successfully applied in a wide range of transition-metal-catalyzed asymmetric reactions, including hydrogenations, carbon-carbon and carbon-heteroatom coupling reactions, with superior or com...

An efficient one-pot three-component procedure for the synthesis of new chiral spiro-oxindolopyrrolizidines with highly regio-, diastereo-, and enantioselective from 1,3-dipolar cycloaddition of azomethine ylides and optically pure active cinamoyl oxazolidinone are described. The process occurs at room temperature in aqueous ethanol as green solvent and in the absence of any bidentate chelating...

An efficient one-pot three-component procedure for the synthesis of new chiral spiro-oxindolopyrrolizidines with highly regio-, diastereo-, and enantioselective from 1,3-dipolar cycloaddition of azomethine ylides and optically pure active cinamoyl oxazolidinone are described. The process occurs at room temperature in aqueous ethanol as green solvent and in the absence of any bidentate chelating...

Journal: :Acta Chimica Sinica 2014

2005
Jian-Hua Xie Shou-Fei Zhu Yu Fu Ai-Guo Hu Qi-Lin Zhou

Chiral spiro phosphorus ligands including monophosphoramidites and diphosphines, which contained 1,1'-spirobiindane as a backbone, were designed and synthesized. These spiro ligands were proven to be highly efficient for rhodiumand ruthenium-catalyzed asymmetric hydrogenations of prochiral olefins and ketones with excellent enantioselectivities.

2017
Guo-Peng Wang Meng-Qing Chen Shou-Fei Zhu Qi-Lin Zhou

Enantioselective control of the chirality of a tertiary a-carbon in the products of a Nazarov cyclization of enones is challenging because the reaction involves an enantioselective proton transfer process. We herein report the use of cooperative catalysis using Lewis acids and chiral Brønsted acids to control the stereochemistry of the tertiary a-carbon in the products of this reaction. Specifi...

Journal: :Chemical communications 2016
Xiao-Xue Sun Hong-Hao Zhang Guo-Hao Li Li Meng Feng Shi

The first catalytic asymmetric [3+2] cyclization of quinone monoimides with olefins has been established, which employed 3-vinylindoles as a class of competent olefins and spiro-chiral phosphoric acid as a powerful chiral catalyst, leading to chemo-, diastereo- and enantioselective construction of a biologically important 2,3-dihydrobenzofuran framework with optical purity (up to 99% yield, >95...

Journal: :Chemical communications 2015
Wei-Peng Liu Ming-Lei Yuan Xiao-Hui Yang Ke Li Jian-Hua Xie Qi-Lin Zhou

Highly efficient iridium catalyzed asymmetric transfer hydrogenation of simple ketones with ethanol as a hydrogen donor has been developed. By using chiral spiro iridium catalysts (S)- a series of alkyl aryl ketones were hydrogenated to chiral alcohols with up to 98% ee.

2017
Lukas Roiser Mario Waser

The use of Cinchona alkaloid-based chiral ammonium ylides allows for the first highly enantioselective and broadly applicable spirocyclopropanation reactions of para-quinone methides. This strategy provides a straightforward protocol toward the chiral spiro[2.5]octa-4,7-dien-6-one skeleton, which is a frequently found structural motif in important biologically active molecules.

Karim Ghafouri, Sajjad Sedaghat, Samira Arab-salmanabadi

Spiro compounds are of interest due to their interesting conformational features and their structural implications on biological systems. The asymmetric characteristic of the molecule due to the chiral spiro carbon is one of the important criteria of the biological activities. These structures are a widespread structural motif found as key elements of numerous drugs and designed medicinal agent...

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