نتایج جستجو برای: imines

تعداد نتایج: 2655  

Journal: :Dalton transactions 2013
Martín Hernández-Juárez Mónica Vaquero Eleuterio Álvarez Verónica Salazar Andrés Suárez

The preparation of new Ru(II) complexes incorporating fac-coordinated lutidine-derived CNC ligands is reported. These derivatives are selectively deprotonated by (t)BuOK at one of the methylene arms of the pincer, leading to catalytically active species in the hydrogenation of imines.

Journal: :Chemical communications 2011
De-Jun Dong Yuan Li Jie-Qi Wang Shi-Kai Tian

A broad range of readily accessible N-sulfonyl imines undergo olefination reaction with nonstabilized phosphonium ylides under mild conditions to afford an array of both Z- and E-isomers of 1,2-disubstituted alkenes, allylic alcohols, and allylic amines in good yields and with greater than 99 : 1 stereoselectivity.

Journal: :Chemical communications 2011
Lianghui Liu Siyu Zhang Xuefeng Fu Chun-Hua Yan

Oxidative coupling of primary amines to imines is achieved with high to moderate yields by refluxing suspensions of amines and water under one atmosphere dioxygen without any additives. Tandem acid-free aza Diels-Alder reactions for synthesis of N-alkyl-4-pyridones are also accomplished.

Journal: :Organic & biomolecular chemistry 2007
A Louise Tillman Darren J Dixon

An enantioselective Brønsted acid catalyzed Mannich reaction between acetophenone derived enamines and N-Boc imines has been developed. Simple diol (S)-H(8)-BINOL has been identified as the optimal catalyst, to afford versatile beta-amino aryl ketones in good yield and enantiomeric excess.

Journal: :Organic & biomolecular chemistry 2014
Wen-Qiang Jia Xiang-Yu Chen Li-Hui Sun Song Ye

The cinchona alkaloid-catalyzed [4 + 2] cyclocondensation of α,β-unsaturated acyl chlorides with imines is developed to give the corresponding substituted dihydropyridinones in good yields with high to excellent enantioselectivities. Reduction of the dihydropyridinones gave highly optically active substituted tetrahydropyridinone and piperidine derivatives.

Journal: :Chemical communications 2011
Juae Han Soyeong Kang Hyeon-Kyu Lee

The dynamic kinetic resolution of 4,5-diaryl cyclic sulfamidate imines was achieved via asymmetric transfer hydrogenation using a HCO(2)H/Et(3)N mixture as the hydrogen source and chiral Rh catalysts (R,R)- or (S,S)-RhCl(TsDPEN)Cp* affording the corresponding cyclic sulfamidates in good yields with up to >20 : 1 dr and up to >99% ee.

Journal: :Dalton transactions 2012
Santhosh Kumar Podiyanachari Roland Fröhlich Constantin G Daniliuc Jeffrey L Petersen Gerald Kehr Gerhard Erker Noriyuki Suzuki Shin Yuasa Keita Hagimori Shota Inoue Takumi Asada Takahiko Takemoto Yoshiro Masuyama

The reaction of η(2)-iminozirconocene chloride complexes with trimethylsilylethynyl lithium leads to rapid C-C coupling at room temperature to yield the corresponding five-membered aza-zirconacycloallenoids. Such compounds were also obtained by trapping of in situ generated zirconocene with alkynyl imines.

2016
Kay Yeung Rebecca E. Ruscoe James Rae Alexander P. Pulis David J. Procter

A highly enantio- and diastereoselective copper-catalyzed three-component coupling affords the first general synthesis of homoallylic amines bearing adjacent stereocenters from achiral starting materials. The method utilizes a commercially available NHC ligand and copper source, operates at ambient temperature, couples readily available simple imines, allenes, and diboranes, and yields high-val...

Journal: :Organic letters 2006
Naidu S Chowdari Moballigh Ahmad Klaus Albertshofer Fujie Tanaka Carlos F Barbas

[reaction: see text] Organocatalytic asymmetric Mannich reaction of protected amino ketones with imines in the presence of an L-proline-derived tetrazole catalyst afforded diamines with excellent yields and enantioselectivities of up to 99%. The amino ketone protecting group controlled the regioselectivity of the reaction providing access to chiral 1,2-diamines from azido ketones and 1,4-diamin...

Journal: :Organic letters 2012
Zhichao Jin Ruojie Yang Yu Du Bhoopendra Tiwari Rakesh Ganguly Yonggui Robin Chi

The first chiral phosphine-catalyzed activation of acrylates for intramolecular formal [2 + 4] reactions with unsaturated imines is described. The catalytic reactions afford N-heterocycles with exceptionally high diastereo- and enantioselectivities. The [2 + 4] products are amenable for further transformations to useful molecules such as chiral piperidines and multicyclic structures.

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