نتایج جستجو برای: asymmetric catalysis

تعداد نتایج: 90956  

2014
Xiaoyu Yang Robert J. Phipps F. Dean Toste

We report a study involving the successful merger of two separate chiral catalytic cycles: a chiral anion phase-transfer catalysis cycle to activate Selectfluor and an enamine activation cycle, using a protected amino acid as organocatalyst. We have demonstrated the viability of this approach with the direct asymmetric fluorination of α-substituted cyclohexanones to generate quaternary fluorine...

Journal: :Journal of the American Chemical Society 2010
Sha Lou Gregory C Fu

The first asymmetric Kumada reactions of alkyl electrophiles are described, specifically, cross-couplings of racemic alpha-bromoketones with aryl Grignard reagents. Several features of this investigation are of interest. First, the couplings proceed at remarkably low temperature (-40 or -60 degrees C), which enables the asymmetric synthesis of racemization-prone alpha-arylketones. Second, dialk...

Journal: :Organic & biomolecular chemistry 2010
Wen Yang Han Liu Da-Ming Du

A combinatorial in situ three-component chiral oxazoline-Schiff base copper(II) complex catalyst formation method was developed. This simple combinatorial chiral catalyst approach provided a modular library of chiral oxazoline-Schiff base copper(II) complex catalysts. The catalytic activity of these in situ generated catalysts can be rapidly and conveniently evaluated in the asymmetric Henry re...

Journal: :Chemistry 2016
Robert Pollice Michael Schnürch

The observation and investigation of nonlinear effects in catalytic reactions provides valuable mechanistic insight. However, the applicability of this method was, until now, limited to molecules possessing chirality and therefore to asymmetric synthesis. The concept of nonlinear effects is expanded to catalytic reactions beyond asymmetric catalysis by using derivatives instead of enantiomers a...

Journal: :Molecules 2016
Pan Li Xinquan Hu Xiu-Qin Dong Xumu Zhang

The organocatalysis-based dynamic kinetic resolution (DKR) process has proved to be a powerful strategy for the construction of chiral compounds. In this feature review, we summarized recent progress on the DKR process, which was promoted by chiral bifunctional (thio)urea and squaramide catalysis via hydrogen-bonding interactions between substrates and catalysts. A wide range of asymmetric reac...

2015
Yingcheng Wang Mingjie Mo Kongxi Zhu Chao Zheng Hongbin Zhang Wei Wang Zhihui Shao

Propargylamines are important intermediates for the synthesis of polyfunctional amino derivatives and natural products and biologically active compounds. The classic method of synthesizing chiral propargylamines involves the asymmetric alkynylation of imines. Here, we report a significant advance in the catalytic asymmetric Mannich-type synthesis of propargylamines through catalytic asymmetric ...

Journal: :Angewandte Chemie 2022

Abstract The application of biocatalysis in conquering challenging synthesis requires the constant input new enzymes. Developing novel biocatalysts by absorbing catalysis modes from synthetic chemistry has yielded fruitful new‐to‐nature Organocatalysis was originally bio‐inspired and become third pillar asymmetric catalysis. Transferring organocatalytic reactions back to enzyme platforms is a p...

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