نتایج جستجو برای: ketoesters

تعداد نتایج: 289  

2011
Lukas Hintermann Mauro Perseghini Antonio Togni

Titanium-based Lewis acids catalyze the α-fluorination of β-ketoesters by electrophilic N-F-fluorinating reagents. Asymmetric catalysis with TADDOLato-titanium(IV) dichloride (TADDOL = α,α,α',α'-tetraaryl-(1,3-dioxolane-4,5-diyl)-dimethanol) Lewis acids produces enantiomerically enriched α-fluorinated β-ketoesters in up to 91% enantiomeric excess, with either F-TEDA (1-chloromethyl-4-fluoro-1,4...

Journal: :Tetrahedron 2014
Sandy Ma Corey M Reeves Robert A Craig Brian M Stoltz

The palladium-catalyzed decarboxylative allylic alkylation of diastereomeric β-ketoesters derived from 4-tert-butylcyclohexanone is described. These experiments were performed to elucidate our understanding of stereoablative enantioconvergent catalysis. A detailed analysis of the product distribution, including stereochemical outcome of the products, is included. These studies also reveal an in...

Journal: :Chemical communications 2013
Xuejian Li Yanyan Zhao Haijun Qu Zhenjun Mao Xufeng Lin

The first catalytic asymmetric pseudo five-component (AB(2)C(2) type) reaction is reported. A spirocyclic chiral phosphoric acid catalyzed one-pot multicomponent reaction of aromatic aldehydes, anilines and β-ketoesters and afforded highly functionalized enantioenriched tetrahydropyridines with high levels of stereocontrol.

Journal: :Bulletin of the Agricultural Chemical Society of Japan 1956

Journal: :Molecules 2009
Chen-Jiang Liu Ji-De Wang

A simple, efficient procedure for the one-pot Biginelli condensation reaction of aldehydes, beta-ketoesters and urea or thiourea employing copper(II) sulfamate as a novel catalyst is described. Compared to the classical Biginelli reaction conditions, the present method has the advantages of good yields, short reaction times and experimental simplicity.

Journal: :Chemical communications 2014
Weiwei Luo Jiannan Zhao Chengkai Yin Xiaohua Liu Lili Lin Xiaoming Feng

An efficient catalytic asymmetric hetero-ene reaction of 5-methyleneoxazolines with 1,2-dicarbonyl compounds (including α-ketoesters and glyoxal derivatives) was realized using Ni(II)-N,N'-dioxide complexes as the catalysts. It provides a rapid, high yielding (up to 99%) route for the preparation of 2,5-disubstituted oxazole derivatives in a highly enantioenriched form (up to >99% ee) under mil...

2015
Łukasz Woźniak John J. Murphy Paolo Melchiorre

The visible-light-driven, phase-transfer-catalyzed, enantioselective perfluoroalkylation and trifluoromethylation of cyclic β-ketoesters is described. The photo-organocatalytic process, which occurs at ambient temperature and under visible light illumination, is triggered by the photochemical activity of in situ-generated electron donor-acceptor complexes, arising from the association of chiral...

Journal: :Chemical communications 2013
Gemma C Geary Eric G Hope Kuldip Singh Alison M Stuart

The air and moisture stable fluoroiodane 8, readily prepared on a 6 g scale by nucleophilic fluorination of the hydroxyiodane 7 with TREAT-HF, has been used as an electrophilic fluorinating reagent for the first time to monofluorinate 1,3-ketoesters and difluorinate 1,3-diketones in good isolated yields.

Journal: :Organic & biomolecular chemistry 2014
M Kamlar S Hybelbauerová I Císařová J Veselý

The highly stereoselective allylic alkylation of Morita-Baylis-Hillman carbonates with β-ketoesters catalysed by β-ICD is described. The corresponding products containing two adjacent quaternary and tertiary carbon centers were obtained in good yields with high diastereoselectivity (up to 10 : 1 dr) and enantioselectivity (up to 95% ee).

Journal: :Journal of the American Chemical Society 2013
Wen-Bo Liu Corey M Reeves Scott C Virgil Brian M Stoltz

Highly congested vicinal stereocenters comprised of tertiary and all-carbon quaternary centers were generated via Ir-catalyzed asymmetric allylic alkylation of β-ketoesters. These catalytic reactions proceed in excellent yields with a broad scope on either reaction partner and with outstanding regio-, diastereo-, and enantiocontrol. Implementation of a subsequent Pd-catalyzed alkylation affords...

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