نتایج جستجو برای: ketones

تعداد نتایج: 9200  

Journal: :Molecules 2017
Cheng Dong Xing-Feng Bai Ji-Yuan Lv Yu-Ming Cui Jian Cao Zhan-Jiang Zheng Li-Wen Xu

It was found that 1,2-trifluoromethylation reactions of ketones, enones, and aldehydes were easily accomplished using the Prakash reagent in the presence of catalytic amounts of cesium carbonate, which represents an experimentally convenient, atom-economic process for this anionic trifluoromethylation of non-enolisable aldehydes and ketones.

Journal: :Chemical communications 2014
Christina M McSweeney Vera M Foley Gerard P McGlacken

The asymmetric alkylation of ketones represents a fundamental transformation in organic chemistry. Chiral auxiliaries have been used almost exclusively for this transformation. Herein we describe a strategy for the generation of enantiomerically enriched α-alkylated ketones up to an er of 83 : 17, using a chiral ligand protocol.

Journal: :Journal of the American Chemical Society 2011
Tianning Diao Shannon S Stahl

α,β-Unsaturated carbonyl compounds are versatile intermediates in the synthesis of pharmaceuticals and biologically active compounds. Here, we report the discovery and application of Pd(DMSO)(2)(TFA)(2) as a catalyst for direct dehydrogenation of cyclohexanones and other cyclic ketones to the corresponding enones, using O(2) as the oxidant. The substrate scope includes heterocyclic ketones and ...

Journal: :Organic & biomolecular chemistry 2016
Shinji Tsunoi Yuta Seo Yugo Takano Itaru Suzuki Ikuya Shibata

A tin-catalyzed reaction of α-hydroxy ketones with 1,1-dicyanoalkenes produced 2-amino-4,5-dihydrofuran-3-nitriles. In the catalytic reaction, tin enolates were generated from α-hydroxy ketones as active catalytic species. The highly basic ability of the Sn-O bonds played an important role in the reactions. This tin-catalyzed reaction was highly atom-economical and required no other metal reage...

Journal: :Tetrahedron letters 2009
Brian M Casey Cynthia A Eakin Robert A Flowers

A straightforward method for the synthesis of gamma-halo-substituted ketones formed via the CAN-initiated oxidative addition of halides to 1-substituted cyclobutanols has been developed. This method has short reaction times, and provides access to a range of bromo and iodo gamma-substituted ketones in good to excellent yields.

Journal: :Organic & biomolecular chemistry 2006
Pawel Dziedzic Weibiao Zou Jonas Háfren Armando Córdova

Simple modular di- and tripeptides with a primary amine at the N-terminus catalyze the aqueous asymmetric aldol reaction between unmodified ketones and aldehydes to furnish the corresponding beta-hydroxy ketones with up to 86% ee in water and 99% ee in aqueous media.

Journal: :Organic & biomolecular chemistry 2013
Somayeh Ahadi Mahdi Zolghadr Hamid Reza Khavasi Ayoob Bazgir

A new method for the synthesis of pyran fused coumarins by 3-bromo-4-hydroxycoumarins as cyclic α-halo ketones based on an organocatalyst assisted three-component tandem reaction is investigated. To the best of our knowledge, cyclic α-halo ketones have not yet been used for the synthesis of pyran fused coumarins.

Journal: :Organic letters 2005
Xiao-jun Wang Li Zhang Xiufeng Sun Yibo Xu Dhileepkumar Krishnamurthy Chris H Senanayake

[chemical reaction: see text]. Direct addition of Grignard reagents to acid chlorides in the presence of bis[2-(N,N-dimethylamino)ethyl] ether proceeds selectively to provide aryl ketones in high yields. A possible tridentate interaction between Grignard reagents and bis[2-(N,N-dimethylamino)ethyl] ether moderates the reactivity of Grignard reagents, preventing the newly formed ketones from nuc...

Journal: :Angewandte Chemie 2015
Martin Pichette Drapeau Indira Fabre Laurence Grimaud Ilaria Ciofini Thierry Ollevier Marc Taillefer

The α-arylation of enolizable aryl ketones can be carried out with aryl halides under transition-metal-free conditions using KOtBu in DMF. The α-aryl ketones thus obtained can be used for step- and cost-economic syntheses of fused heterocycles and Tamoxifen. Mechanistic studies demonstrate the synergetic role of base and solvent for the initiation of the radical process.

Journal: :Chemical communications 2016
Yu-Chang Liu Zhong-Liu Wu

Efficient asymmetric bio-epoxidation of electron-deficient α,β-unsaturated ketones was realized via a tandem reduction-epoxidation-dehydrogenation cascade, which proceeds in a switchable manner to afford either chiral epoxy ketones or allylic epoxy alcohols with up to >99% yield and >99%ee.

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید