Blue‐Light Irradiated Mn(0)‐Catalyzed Hydroxylation and C(sp³)−H Functionalization of Unactivated Alkanes with C(sp²)−H Bonds of Quinones for Alkylated Hydroxy Quinones and Parvaquone

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 30(12)

Published: Nov. 23, 2023

Abstract Site‐selective C( sp 3 )−H functionalization of unreactive hydrocarbons is always challenging due to its inherited chemical inertness, slightly different reactivity various C−H bonds, and intrinsically high bond dissociation energies. Here, a site‐selective alkylation naphthoquinone with unactivated using Mn 2 (CO) 10 as catalyst under blue‐light (457 nm) irradiation without any external acid or base pre‐functionalization presented. The selective tertiary over secondary primary bonds in abundant feedstocks was achieved, hydroxylation quinones realized situ by employing the developed methodology. This protocol provides new catalytic system for direct construction high‐value‐added compounds, namely, parvaquone (a commercially available drug used treat theileriosis ) derivatives ambient reaction conditions. Moreover, this operationally simple applies linear‐, branched‐, cyclo‐alkanes degrees site selectivity irradiated conditions could provide rapid straightforward access versatile methodologies upgrading feedstock chemicals. Mechanistic insight radical trapping, scavenging, EPR, other controlled experiments well corroborated DFT studies suggest that proceeds pathway.

Language: Английский

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Visible-Light Photocatalytic Barbier-Type Reaction of Aziridines and Azetidines with Nonactivated Aldehydes

Synlett, Journal Year: 2023, Volume and Issue: 34(12), P. 1385 - 1390

Published: Feb. 21, 2023

Abstract Barbier-type reactions are a classic group of for carbon–carbon bond formation; however, their common use stoichiometric metals restricts widespread application. Considering the ready availability and diversity cyclic amines, we report visible-light photocatalytic reaction aziridines azetidines with nonactivated aldehydes. A series important γ- δ-amino alcohols were synthesized in presence amines as electron donors. Moreover, this transition-metal-free protocol displays mild conditions, broad functional-group tolerance, wide substrate scope. Mechanistic investigations indicated that carbon radicals carbanions might be generated key intermediates.

Language: Английский

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Site‐selective Photoredox‐Catalyzed Late‐stage Benzylic Hydrogen Isotope Exchange

Angewandte Chemie, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 30, 2024

Abstract Es wird ein hochgradig regioselektiver, von sichtbarem Licht photoredox‐katalysierter Wasserstoff‐isotopenaustausch (WIA) an benzylischen Positionen einfachen und komplexen Molekülen beschrieben. Der Prozess folgt einem dual katalytischen Ansatz, basierend auf der Kombination eines Acridinium‐Photokatalysators mit Thiol basierten Wasserstoffatomtransfer Katalysator (HAT). Die Verwendung D 2 O als Isotopenquelle gewährleistet hierbei eine einfache Handhabung Kosteneffizienz. konnte hohe Reaktivität für elektronenreiche benzylische erreicht werden. gezielte Bildung Radikalen ermöglicht einen selektiven WIA intramolekular konkurrierenden Benzyl‐ alpha zu Heteroatom‐positionen moderatem bis ausgezeichnetem Deuteriumeinbau. Nutzen dieser Reaktion wurde durch verschiedenen Naturstoff‐ Arzneimittelderivaten demonstriert. Experimentelle Studien Dichtefunktionaltheorieberechnungen (DFT) legen Ein‐Elektronen‐Übertragungsmechanismus (SET) nahe, gefolgt einer Deprotonierung zur des Radikals. Hierbei die Bedeutung halogenierten Lösungsmitteln oder Additiven demonstriert schwache Interaktion Halogenspezies dem Substrat führt Komplexes. Dies resultiert in Senkung Oxidationspotenzials Stabilisierung Radikal‐Kation‐Spezies Spin‐Delokalisierung.

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Method Development and Syntheses Examples of Isotopically Labeled Compounds to Foster Operational Excellence in Pharma Industry

Synlett, Journal Year: 2023, Volume and Issue: 35(19), P. 2155 - 2173

Published: Dec. 4, 2023

Abstract The different topics and synthetic approaches in an isotope chemistry laboratory of a pharma company are described. Besides the challenges synthesis long-lived isotopes such as 3H or 14C, short-lived 68Ga stable 15N, 13C 2H for isotopic labeling also demonstrated. Furthermore, method development with emphasis on collaborations academic groups to tackle future discussed. 1 Introduction 2 Isotopic Labeling Hydrogen Isotopes Deuterium (2H, D) Tritium (3H, T) 2.1 MS Standards 2.1.1 Labeled Nitrosamines – Hunt Quantify Hazardous Impurities 2.1.2 Deuterated Drugs, Approach To Improve Existing Drugs Find Opportunities Drug Discovery 2.2 Tritium-Labeling Methods Fast Radioactively Compounds 2.2.1 Isotope Exchange by Iridium Catalysis 2.2.2 Ruthenium-Catalyzed HIE 2.2.3 Nanoparticles Catalysts 2.2.4 Photoredox-Catalyzed 2.2.5 via Classical Radical Mechanism 2.2.6 Beyond Halogen–Tritium 3 Challenges 14C-Synthesis Projects 4 Short-Lived Need Speed 5 Science Late-Stage Functionalization 5.1 Examples Peptides 5.2 Catalyst-Controlled 6 Conclusion

Language: Английский

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Cobalt(II)-Catalyzed Selective Three-Component Oxyalkylation of N-Aryl Glycinates: A Route to CF₃-Labeled Threonine Analogues

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(24), P. 17010 - 17023

Published: Nov. 30, 2023

Glycinates, protected enols, and an electrophilic trifluoromethylating reagent were employed to assemble CF3-labeled threonine analogues through a radical addition cascade. To suppress the competing oxidation of oxyalkyl intermediate, various redox catalysts evaluated Co(II) exhibited supreme selectivity control with proper counterion. A series glycinate related peptides thus successfully modified under Co-catalysis. Mechanistic studies revealed that N-aryl could be preferentially oxidized by cobalt over generate imine key this ascribed prechelation glycinate, as well weakly basic carboxylate

Language: Английский

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