Results 21 to 30 of about 16,892 (273)

Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

Beilstein Journal of Organic Chemistry, 2021
A new highly diastereoselective synthesis of the polyhydroxylated pyrrolidine alkaloid (±)-codonopsinol B and its N-nor-methyl analogue, starting from achiral materials, is presented.
Lukáš Ďurina, Anna Ďurinová, František Trejtnar, Ľuboš Janotka, Lucia Messingerová, Jana Doháňošová, Ján Moncol, Róbert Fischer   +7 more
doaj   +1 more source

Enantioselective Synthesis of Axially Chiral Diaryl Ethers via Rhodium‐Catalyzed [2 + 2 + 2] Cycloaddition

Angewandte Chemie, EarlyView.
An enantioselective rhodium‐catalyzed [2 + 2 + 2] cycloaddition enables the synthesis of axially chiral diaryl ethers. Carbonyl coordination ensures high reactivity and regioselectivity, affording products bearing up to four stereogenic axes with good enantio‐ and diastereoselectivity.
Yu Sato, Julong Jiang, Kairi Yamashiro, Ken Tanaka   +3 more
wiley   +2 more sources

Asymmetric Iron‐Catalyzed Vicinal C(sp3)─H Diamination of Carboxylic Acids

Angewandte Chemie, EarlyView.
An iron‐catalyzed vicinal α,β‐C(sp3)─H diamination of readily available carboxylic acids furnishes chiral α,β‐diamino acids in a single pot with high regio‐, diastereo‐, and enantioselectivity (up to >20:1 dr and >99% ee). ABSTRACT The direct construction of chiral 1,2‐diamines through the stereoselective functionalization of two vicinal C(sp3)─H bonds
Bing Zhou, Yuan Zheng, Xiulan Xie, Marcel Hemming, Sergei I. Ivlev, Eric Meggers   +5 more
wiley   +2 more sources

Catalytic Functionalization of Unactivated π‐Bonds Enabled by Bidentate Directing Auxiliaries

Angewandte Chemie, EarlyView.
This review explores how bidentate directing auxiliaries have advanced transition‐metal catalysis for unactivated alkene/alkyne functionalization. By leveraging chelated intermediates, bidentate directing auxiliaries enable precise hydrofunctionalization, difunctionalization, and C─H activation of π‐bonds with unique selectivity and reactivity.
Seunghyeon Cho, Al Vicente Riano D. Lisboa, Juntao Sun, Taeho Kang, Keary M. Engle   +4 more
wiley   +2 more sources

The tert-butylaminomethyl(mesityl)phosphinic acid ester and formation of its zinc dichloride complex: syntheses and characterization

Main Group Metal Chemistry, 2018
The syntheses and structures of tert-butylaminomethyl(mesityl)phosphinic acid ethyl ester 2 and its zinc dichloride complex 3 are reported. In the solid state, both compounds are dimeric via hydrogen bridges. In the complex 3, the phosphinic acid ester 2
Lutter Michael, Stratmann Lukas M., Jurkschat Klaus   +2 more
doaj   +1 more source

Acid controlled diastereoselectivity in asymmetric aldol reaction of cycloketones with aldehydes using enamine-based organocatalysts

, 2011
Acid controlled diastereoselectivity in asymmetric aldol reaction of cycloketones with aldehydes using enamine-based organocatalystsThe example of syn-aldol reaction of cyclohexanone to aldehyde was demonstrated based on chiral diamine organocatalysts ...
Liu, Yan, 刘, 杨启华, Gao, Qiang, Gao, Jinsuo, Yang, Qihua, Bai, Shiyang   +6 more
core   +1 more source

3‐Deoxy‐3‐Fluoro Mannuronic Acid Alginates: Stereoselective Automated Synthesis and Conformational Behaviour

Angewandte Chemie, EarlyView.
The impact of C‐3 fluorination on the synthesis and conformation of alginate oligosaccharides is investigated. A C‐3‐fluoro mannuronic acid building block is generated and shown to react with high β‐selectivity. Automated glycan assembly enables access to uniquely fluorinated mannuronic acid alginates where deoxyfluorination is shown not to perturb the
Sean T. Evans, Nishu Yadav, Wouter A. Remmerswaal, Daan Hoogers, Koen N. A. van de Vrande, Sarah Hosking, Ana Poveda, Jeroen D. C. Codée, Jesús Jiménez‐Barbero, Martina Delbianco, Gavin J. Miller   +10 more
wiley   +2 more sources

Diastereoselective Addition of Diazomethane to Zaluzanin A [PDF]

Natural Product Communications, 2014
The diastereoselectivity of diazomethane addition to the conjugated double bond of α,β-unsaturated sesquiterpene lactones was explored using zaluzanin A (1) as a model. Thus, the absolute configuration of 1 was assured by X-ray diffraction analysis including evaluation of Flack and Hooft parameters, and by vibrational circular ...
Adriana, Ortiz-León, J Martín, Torres-Valencia, J Jesús, Manríquez-Torres, José G, Alvarado-Rodríguez, Uvaldo, Hernández-Balderas, Carlos M, Cerda-García-Rojas, Pedro, Joseph-Nathan   +6 more
openaire   +2 more sources

Felkin-Anh Model from an Orbital Phase Perspective: Diastereoselectivity in Nucleophilic Addition to 2,3-Bis(trifluoromethyl)bicyclo[2.2.1]heptan-7-one

, 2019
To address the electronic effect in nucleophilic addition, we often use the Felkin-Anh model, in which the most sigma-electron-withdrawing group (.sigma.EWG) at the a-position of the carbonyl should be located anti to the nucleophile approach.
Yuji, Naruse, Hayata, Hibino, Atsushi, Takamori   +2 more
core   +1 more source

Catalytic Enantioselective Intramolecular Aza‐Michael Addition to α,β‐Unsaturated Esters

Angewandte Chemie, EarlyView.
A general method for accessing enantioenriched saturated N‐heterocycles via a catalytic enantioselective intramolecular aza‐Michael reaction to α,β‐unsaturated esters is described. A superbasic bifunctional iminophosphorane (BIMP) catalyst was key to enabling reactivity of the high pKa sulfonamide pronucleophile, whilst delivering good to excellent ...
Evan G. W. Rutter, Cameron J. MacRae, Haoran Xiong, Daniel Rozsar, Katherine F. P. Clarke, Darren J. Dixon   +5 more
wiley   +2 more sources