نتایج جستجو برای: diels alder reaction

تعداد نتایج: 415019  

Journal: :Organic letters 2014
Barrie J Marsh Harry Adams Mike D Barker Ibrahim U Kutama Simon Jones

A highly enantioselective (>95% ee) strategy to affect the desymmetrization of a maleimide has been performed by temporary attachment to an anthracene template followed by asymmetric reduction with an oxazaborolidine catalyst. A stereoablative over-reduction process was partially responsible for the high levels of enantioselectivity. Exemplification of the strategy by stereoselective functional...

Journal: :Organic & biomolecular chemistry 2014
Xiubing Liu Lingling Hu Xiaojing Liu Junhao Jia Lizhen Jiang Jiangfeng Lin Xiaochuan Chen

A useful and flexible strategy for synthesis of (-)- and (+)-infectocaryone from commercial sugars is developed. The key step of the synthesis is a new-type Diels-Alder reaction with good chemoselectivity and stereoselectivity, in which a mixture of alkene regioisomers in a dynamic equilibrium is employed as chiral dienophiles for the first time.

Journal: :Chemical communications 2016
Nils Wedler-Jasinski Thorsten Lueckerath Hatice Mutlu Anja S Goldmann Andreas Walther Martina H Stenzel Christopher Barner-Kowollik

We introduce the fully reversible folding of single chain nanoparticles (SCNPs) based on covalent hetero Diels-Alder (HDA) chemistry. A cyclopentadiene (Cp)-protected cyanodithioester (CDTE) monomer is designed and copolymerized with methyl methacrylate (MMA) via RAFT polymerization. The polymer chains are folded and subsequently unfolded by exploiting the reversible nature of the HDA reaction.

Journal: :Organic letters 2011
Hui Lv Junming Mo Xinqiang Fang Yonggui Robin Chi

Highly enantioselective (formal) hetero-Diels-Alder reactions between chalcones and formylcyclopropanes are disclosed. The challenging N-heterocyclic carbene (NHC)-bounded enolate intermediates from formylcyclopropanes were captured for new C-C bond forming reactions. The reaction products were obtained with high diastereo- and enantioselectivities and could be easily transformed to optically p...

Journal: :Organic letters 2002
Qingwei Yao

A general and highly efficient synthesis of cyclic sulfones based on ring-closing metathesis has been developed. The synthetic utility of the resulting cyclic sulfones was demonstrated by their participation in stereoselective Diels-Alder reactions and transformation to cyclic dienes by the Ramberg-Bäcklund reaction.

Journal: :Colloids and Surfaces A: Physicochemical and Engineering Aspects 2022

Stimuli-responsive polymers, with properties changing upon different environmental factor variations such as pH, light, mechanical stress or temperature, and polymeric nanoparticles have found many important applications in fields drug delivery, biosensing research. In this work, thermoresponsive that are able to react by Diels-Alder reaction (a diene-dienophile cycloaddition) were studied. The...

Journal: :Chemical & pharmaceutical bulletin 2001
T Yoshida A Ito K Ibusuki M Murase E Kotani

Sulfur substituted 3-vinylpyrrole 10 was prepared from 3-thio-acetylpyrrole 9 by alkylation with alkyl halide in the presence of propylene oxide. Functionalized 4-alkylthioindoles were made by Diels-Alder reaction of the 3-vinylpyrrole 10 with dienophiles. Chuangxinmycin analogues were synthesized by using some of the functionalized 4-alkylthioindoles as key intermediates.

Journal: :Chemical communications 2010
Iván González Anna Pla-Quintana Anna Roglans Anna Dachs Miquel Solà Teodor Parella Jordi Farjas Pere Roura Vega Lloveras José Vidal-Gancedo

A domino process is described combining an ene reaction between two alkynes and a Diels-Alder cycloaddition of the vinylallene formed. The process accounts for the thermally induced cycloisomerization of macrocyclic triynes and enediynes to give fused tetracycles in a stereoselective manner.

Journal: :Zeitschrift fur Naturforschung. C, Journal of biosciences 2012
Margarita Gutiérrez Unai Carmona Gabriel Vallejos Luis Astudillo

Seven synthetic tetrahydroquinolines with different substitution patterns were obtained by an imino Diels-Alder condensation reaction and were evaluated against phytopathogenic fungi. Compounds with a methoxy group showed interesting activity against Cladosporium cladosporoides with a MIC value of 13.75 microg/mL

2014
Arun K. Ghosh Nianchun Ma Kerstin A. Effenberger Melissa S. Jurica

An enantioselective total synthesis of GEX1Q1 has been accomplished in a convergent manner. The C-5 asymmetric center has now been assigned through synthesis. GEX1Q1 displayed slightly better spliceosome inhibitory activity over its C-5 epimer. The salient features of this synthesis include an asymmetric hetero-Diels-Alder reaction to construct the tetrahydropyran ring and a Suzuki cross-coupli...

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