- Site-Specific C(sp3)–H Aminations of Imidates and Amidines Enabled by Covalently Tethered Distonic Radical Anions
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The utilization of N-centered radicals to synthesize nitrogen-containing compounds has attracted considerable attention recently, due to their powerful reactivities and the concomitant construction of C?N bonds. However, the generation and control of N-centered radicals remain particularly challenging. We report a tethering strategy using SOMO-HOMO-converted distonic radical anions for the site-specific aminations of imidates and amidines with aid of the non-covalent interaction. This reaction features a remarkably broad substrate scope and also enables the late-stage functionalization of bioactive molecules. Furthermore, the reaction mechanism is thoroughly investigated through kinetic studies, Raman spectroscopy, electron paramagnetic resonance spectroscopy, and density functional theory calculations, revealing that the aminations likely involve direct homolytic cleavage of N?H bonds and subsequently controllable 1,5 or 1,6 hydrogen atom transfer.
- Fang, Yuanding,Fu, Kang,Shi, Lei,Zhao, Rong,Zhou, Jia
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p. 20682 - 20690
(2020/09/07)
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- Copper(I) Phosphinooxazoline Complexes: Impact of the Ligand Substitution and Steric Demand on the Electrochemical and Photophysical Properties
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A series of seven homoleptic CuI complexes based on hetero-bidentate P^N ligands was synthesized and comprehensively characterized. In order to study structure–property relationships, the type, size, number and configuration of substituents at the phosphinooxazoline (phox) ligands were systematically varied. To this end, a combination of X-ray diffraction, NMR spectroscopy, steady-state absorption and emission spectroscopy, time-resolved emission spectroscopy, quenching experiments and cyclic voltammetry was used to assess the photophysical and electrochemical properties. Furthermore, time-dependent density functional theory calculations were applied to also analyze the excited state structures and characteristics. Surprisingly, a strong dependency on the chirality of the respective P^N ligand was found, whereas the specific kind and size of the different substituents has only a minor impact on the properties in solution. Most importantly, all complexes except C3 are photostable in solution and show fully reversible redox processes. Sacrificial reductants were applied to demonstrate a successful electron transfer upon light irradiation. These properties render this class of photosensitizers as potential candidates for solar energy conversion issues.
- Frey, Wolfgang,Giereth, Robin,Karnahl, Michael,Klo?, Marvin,Mengele, Alexander K.,Steffen, Andreas,Tschierlei, Stefanie
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p. 2675 - 2684
(2020/03/04)
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- A Short Access to Symmetrically α,α-Disubstituted α-Amino Acids from Acyl Cyanohydrins
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A straightforward synthesis of symmetrically α,α-disubstituted α-amino acids is presented. The key step of this process relies on the efficient double addition of Grignard reagents to acyl cyanohydrins to provide N-acyl amino alcohols selectively in good yields. The chemoselectivity of the reaction was modulated by the nature of the acyl moiety. Eleven amino acids were prepared, including the particularly simple divinylglycine, which is not easily accessible by using conventional methods.
- Boukattaya, Fatma,Caillé, Julien,Ammar, Houcine,Rouzier, Florian,Boeda, Fabien,Pearson-Long, Morwenna S. M.,Bertus, Philippe
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p. 906 - 916
(2016/03/12)
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- An improved and mild wenker synthesis of aziridines
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The conventional Wenker synthesis of aziridines from vicinal amino alcohols has been modified by employing mild reaction conditions. Amino alcohols were converted into their hydrogen sulfates with chlorosulfonic acid. The sulfates were cyclized with sodium hydroxide, and even with non-nucleophilic sodium carbonate. The current, improved method extends the scope of the typical Wenker synthesis and is applicable to unstable amino alcohols in hot sulfuric acid and to unstable sulfates which favor elimination and hydroxide displacement in the presence of strong base. Georg Thieme Verlag Stuttgart.
- Li, Xinyao,Chen, Ning,Xu, Jiaxi
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body text
p. 3423 - 3428
(2010/11/21)
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- Synthesis and use of achiral oxazolidine-2-thiones in selective preparation of trans 2,5-disubstituted tetrahydrofurans
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The use of achiral N-acetyloxazolidine-2-thiones in the C-glycosylation of lactol acetates has allowed us to prepare with high diastereoselectivity the expected trans 2,5-disubstituted tetrahydrofurans. A study based on the role of the steric hindrance of the N-acetyloxazolidine-2-thiones is reported. Wiley-VCH Verlag GmbH & Co. KGaA, 2009.
- Jalce, Gael,Franck, Xavier,Figadere, Bruno
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body text
p. 378 - 386
(2009/09/25)
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- Proline-catalyzed highly enantioselective and anti-selective mannich reaction of unactivated ketones: Synthesis of chiral α-amino acids
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(Chemical Equation Presented) Universal L-proline: The title reaction complements well-known syn-selective Mannich reactions. The Mannich products can be converted readily into the free amino acids by hydrogenolytic deprotection under mild conditions (see scheme). DMSO = dimethyl sulfoxide; R1 = alkyl, OH; R2 = alkyl.
- Hahn, Bjoern T.,Froehlich, Roland,Harms, Klaus,Glorius, Frank
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supporting information; experimental part
p. 9985 - 9988
(2009/04/21)
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- Versatile synthesis of free and N-benzyloxycarbonyl-protected 2,2-disubstituted taurines
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An effective and versatile method was developed to synthesize N-benzyloxycarbonyl-protected and free 2,2-disubstituted taurines. Several novel 2,2-disubstituted taurines, including aliphatic/aromatic and cyclic/acyclic derivatives, were obtained, which demonstrates the generality of this method. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Wang, Boyuan,Zhang, Wei,Zhang, Leilei,Du, Da-Ming,Liu, Gang,Xu, Jiaxi
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p. 350 - 355
(2008/09/18)
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- N-Phosphoryl oxazolidinones as effective phosphorylating agents
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A number of N-phosphoryl oxazolidinones have been prepared and evaluated, the best being 5,5-diphenyl oxazolidinones, the utility of which was demonstrated in the phosphorylation of a number of representative primary, secondary, tertiary, and phenolic alcohols.
- Jones, Simon,Smanmoo, Chaiwat
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p. 1585 - 1588
(2007/10/03)
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- Unprecedented effects of achiral oxazolidinones on enantioselective radical-mediated conjugate additions using a chiral zinc triflate
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equation presented A role of achiral oxazolidinones to enhance the enantioselectivity in reactions of N-cinnamoyloxazolidinones with alkyl radicals promoted by a chiral Lewis acid is described. Efficient enantioselective radical-mediated conjugate additio
- Murakata, Masatoshi,Tsutsui, Hideyuki,Hoshino, Osamu
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p. 299 - 302
(2007/10/03)
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- Oxazolidinones as alpha 1A receptor antagonists
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This invention is directed to oxazolidinone compounds which are selective antagonists for human alpha 1A receptors. This invention is also related to uses of these compounds for lowering intraocular pressure, inhibiting cholesterol synthesis, relaxing lower urinary tract tissue, the treatment of benign prostatic hyperplasia, impotency, cardiac arrhythmia and for the treatment of any disease where the antagonism of the alpha 1A receptor may be useful. The invention further provides a pharmaceutical composition comprising a therapeutically effective amount of the above-defined compounds and a pharmaceutically acceptable carrier.
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