نتایج جستجو برای: ketones

تعداد نتایج: 9200  

Journal: :Organic & biomolecular chemistry 2011
De-Wei Wang Siang-en Syu Yi-Ting Hung Pei-yi Chen Chia-Jui Lee Ko-Wei Chen Yu-Jhang Chen Wenwei Lin

An EtPPh(2)- or PPh(3)-catalyzed tandem three-component reaction of aldehyde, alkyl vinyl ketone, and amide is developed. Its further application in one-pot syntheses of highly functional alkenes starting from aldehydes, alkyl vinyl ketones, and amides is realized. A wide variety of highly functional α,β-unsaturated ketones can be furnished in 68-99% yields with high stereoselectivity (E/Z up t...

Journal: :Organic & biomolecular chemistry 2011
Xiaohu Zhao Delong Liu Fang Xie Yangang Liu Wanbin Zhang

Palladium-catalyzed asymmetric allylic alkylation of ketones, via enamines generated in situ as nucleophiles, were carried out smoothly with chiral metallocene-based P,N-ligands. Under the same conditions, however, reactions of aldehydes could hardly be observed. Subsequently, this obstacle was resolved by using chiral metallocene-based P,P-ligands. Both ketones and aldehydes afforded excellent...

2011
Mikail E. Abbasov Daniel Romo

One of the most powerful synthetic transformations with the ability to stereospecifically create new carbon-carbon bonds by simple orbital reorganization are electrocyclic reactions. One of the most recognized electrocyclic reactions is known as Nazarov cyclization. This reaction involves the conversion of divinyl ketones to cyclopentenones by activation with a Brønsted or Lewis acid. It was or...

Journal: :The Journal of organic chemistry 2006
Jingjun Yin Mark A Huffman Karen M Conrad Joseph D Armstrong

[reaction: see text] Very practical synthesis of ephedrine analogues in high yields and enantiopurity was realized by a highly diastereoselective Meerwein-Ponndorf-Verley (MPV) reduction of protected alpha-amino aromatic ketones using catalytic aluminum isopropoxide. The high anti selectivity resulted from the chelation of the nitrogen anion to the aluminum. In contrast, high syn selectivity wa...

2012
Sheikh Abdul Majid Waheed Ahmad Khanday Radha Tomar

A simple and versatile method for the synthesis of 1,5-benzodiazepines is via condensation of o-phenylenediamines (OPDA) and ketones in the presence of catalytic amount of H-MCM-22 using acetonitrile as solvent at room temperature. In all the cases, the reactions are highly selective and are completed within 1-3 h. The method is applicable to both cyclic and acyclic ketones without significant ...

Journal: :Angewandte Chemie 2014
Fu-Lin Zhu Yuan Zou De-Yang Zhang Ya-Hui Wang Xin-Hu Hu Song Chen Jie Xu Xiang-Ping Hu

The first enantioselective copper-catalyzed decarboxylative propargylic alkylation has been developed. Treatment of propargyl β-ketoesters with a catalyst, prepared in situ from [Cu(CH3 CN)4 BF4 ] and a newly developed chiral tridentate ketimine P,N,N-ligand under mild reaction conditions, generates β-ethynyl ketones in good yields and with high enantioselectivities without requiring the pregen...

Journal: :Organic letters 2013
Steven Bloom Cody Ross Pitts Ryan Woltornist Andrew Griswold Maxwell Gargiulo Holl Thomas Lectka

Direct C-F functionalization of benzylic sp(3) C-H bonds is a synthetic challenge that has yet to be propitiously overcome. A mild, one-pot synthesis of monofluorinated benzylic substrates is reported with commercially available iron(II) acetylacetonate and Selectfluor in good to excellent yields and selectivity. A convenient route to β-fluorinated products of 3-aryl ketones is also highlighted...

Journal: :Chemical communications 2014
Aline Utaka Livia N Cavalcanti Luiz F Silva

A new method for the electrophilic α-alkynylation of ketones was developed using hypervalent iodine under mild and metal-free conditions. Carbonyl compounds containing an α-acetylene group were obtained in good to excellent yields for several ketones using 1-[(trimethylsilyl)ethynyl]-1,2-benziodoxol-3(1H)-one (TMS-EBX) as an alkynylation agent in the presence of t-BuOK and TBAF in THF as solven...

Journal: :Molecules 2014
Damiano Rocchi Juan F González J Carlos Menéndez

An environmentally benign, clean and general protocol was developed for the synthesis of aryl and heteroaryl trans-chalcones. This method involved solvent-free reaction conditions under microwave irradiation in the presence of a clay-based catalyst, and afforded the target compounds in good yields and short reaction times. Furthermore, the same conditions allowed the synthesis of symmetrical, d...

Journal: :Chemistry 2016
Amparo Sanz-Marco Gonzalo Blay M Carmen Muñoz José R Pedro

The first catalytic enantioselective conjugate alkynylation of α,β-unsaturated 1,1,1-trifluoromethyl ketones has been carried out. Terminal alkynes and 1,3-diynes were treated with trifluoromethyl ketones in the presence of a low catalytic load of a Cu(I) -MeOBIPHEP complex (2.5 mol %) and triethylamine (10 mol %) to give the corresponding trifluoromethyl ketones bearing a propargylic stereogen...

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