نتایج جستجو برای: stereoselective

تعداد نتایج: 4707  

Journal: :Molecular Catalysis 2021

2-Arylpropionic acid derivatives, such as ibuprofen, constitute an important group of non-steroidal anti-inflammatory drugs (NSAIDs). Biocatalytic asymmetric reduction 2-arylacrylic derivatives by ene reductases (EREDs) is a valuable approach for synthesis these derivatives. However, previous bioreduction EREDs resulted solely in nonpharmacological (R)-enantiomers. Here, we present the engineer...

Journal: :Chemical communications 2005
Kevin P Cole Richard P Hsung

Stereoselective and transannular reactivities are described for the ABD tricyclic manifold of phomactin A that possesses a unique structural topology.

Journal: :Chemical communications 2010
Bo Chen Lu Dai Hui Zhang Wenfei Tan Zhengshuang Xu Tao Ye

A convergent approach leading to the stereoselective synthesis of four diastereomers of lydiamycin A has been established and verified.

1991
Alexander J. Fatiadi

The objective of this review is to provide a current overview of the rapidly developing chemistry of organometallic complexes and particularly organoiron complexes useful in asymmetric and stereoselective reactions. Also covered are stereoselective reactions of α, β-unsaturated acyl ligands bound to the chiral auxiliary [(η5-C5H5) Fe(CO)(PPh3)] and new applications of organoiron complexes in th...

2015
Marco Giulio Rigamonti Francesco Gilberto Gatti

The first stereoselective synthesis of lippidulcines A, B and C has been accomplished starting from (+)-hernandulcin, which has been prepared on a multigram scale. The previously assigned absolute configurations have been confirmed. The key steps of this synthesis are based on a modified version of the Kornblum-DeLaMare rearrangement, and on a highly regioselective and stereoselective ketone re...

Journal: :Angewandte Chemie 2014
Marius Mewald Jonathan William Medley Mohammad Movassaghi

We report an efficient and highly stereoselective strategy for the synthesis of Aspidosperma alkaloids based on the transannular cyclization of a chiral lactam precursor. Three new stereocenters are formed in this key step with excellent diastereoselectivity due to the conformational bias of the cyclization precursor, leading to a versatile pentacyclic intermediate. A subsequent stereoselective...

2015
Xin-Hu Hu Zhen-Ting Liu Long Shao Xiang-Ping Hu

Abstract Terminal propargylic compounds containing an alkyne unit and an alcohol or ester group in the propargylic position have a fairly acidic acetylenic hydrogen atom; this makes them versatile substrates for further chemical transformation. Some transition metals such as ruthenium or copper exhibit specific affinity for terminal propargylic compounds, generating dielectrophilic ruthenium– o...

Journal: :Chemistry, an Asian journal 2013
Yoshiaki Miyamoto Norihiro Wada Takahiro Soeta Shuhei Fujinami Katsuhiko Inomata Yutaka Ukaji

The stereoselective direct transformation of N-(propargylic)hydroxylamines into cis-2-acylaziridines was achieved by the combined use of AgBF4 and CuCl. Copper salts were found to promote the transformation of the intermediary 4-isoxazolines into 2-acylaziridines and both 3-aryl- and 3-alkyl-substituted 2-acylaziridines could be prepared by using this method. Furthermore, subsequent 1,3-dipolar...

Journal: :Organic & biomolecular chemistry 2012
Sajjad Ahmad Michael D Swift Louis J Farrugia Hans Martin Senn Andrew Sutherland

A new synthetic approach has been developed for the preparation of 7-deoxypancratistatin analogues bearing a syn-(4aS,10bS)-phenanthridone ring junction. A one-pot tandem process involving a substrate-directed Overman rearrangement and ring closing metathesis reaction was developed for the stereoselective synthesis of a carbocyclic allylic trichloroacetamide. Conversion to a 6-bromopiperonyl am...

Journal: :Organic & biomolecular chemistry 2011
Mark Daly Kathryn Gill Mairi Sime Graham L Simpson Andrew Sutherland

A new flexible approach for the stereoselective synthesis of substituted 1H-pyrrol-2(5H)-ones and 3,6-dihydro-1H-pyridin-2-ones has been developed. The general strategy employed the stereoselective reduction of a series of α,β-unsaturated ketones under chelation control to give the corresponding allylic alcohols. Overman rearrangement to install the key C-N bond followed by conversion to either...

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