Stable Meisenheimer Complexes as Powerful Photoreductants Readily Obtained from Aza‐Heteroaromatic Compounds DOI Creative Commons
Francesco Calogero,

Leonie Wilczek,

Emanuele Pinosa

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(44)

Published: July 30, 2024

Abstract Excited states of radical anions derived from the photoreduction stable organic molecules are suggested to serve as potent reductants. However, excited these species too short‐lived allow bimolecular quenching processes. Recently, singlet state Meisenheimer complexes, which possess a long‐lived state, was identified competent for reduction challenging substrates (−2.63 V vs. SCE, saturated calomel electrode). To produce reasonably and simply accessible different addition n BuLi readily available aromatic heterocycles investigated, photoreactivity generated studied. In this paper, we present straightforward preparation family powerful photoreductants (*E ox < −3 SCE in their states, determined by DFT time‐dependent TD‐DFT calculations; DFT, density functional theory) that can induce dehalogenation electron‐rich aryl chlorides form C−C bond through cyclization. Photophysical analyses computational studies combination with experimental mechanistic investigations demonstrate ability adduct act strong electron donor under visible light irradiation.

Language: Английский

Nickel-Catalyzed Enantioselective Electrochemical Reductive Cross-Coupling of Aryl Aziridines with Alkenyl Bromides DOI Creative Commons

Hu Xia,

Iván Cheng‐Sánchez, Sergio Cuesta‐Galisteo

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(11), P. 6270 - 6279

Published: March 7, 2023

An electrochemically driven nickel-catalyzed enantioselective reductive cross-coupling of aryl aziridines with alkenyl bromides has been developed, affording enantioenriched β-aryl homoallylic amines excellent E-selectivity. This electroreductive strategy proceeds in the absence heterogeneous metal reductants and sacrificial anodes by employing constant current electrolysis an undivided cell triethylamine as a terminal reductant. The reaction features mild conditions, remarkable stereocontrol, broad substrate scope, functional group compatibility, which was illustrated late-stage functionalization bioactive molecules. Mechanistic studies indicate that this transformation conforms stereoconvergent mechanism aziridine is activated through nucleophilic halide ring-opening process.

Language: Английский

Citations

89
Stereodynamic Strategies to Induce and Enrich Chirality of Atropisomers at a Late Stage DOI
Casey B. Roos, Chang-Hwa Chiang, Lauren A. M. Murray

et al.

Chemical Reviews, Journal Year: 2023, Volume and Issue: 123(17), P. 10641 - 10727

Published: Aug. 28, 2023

Enantiomers, where chirality arises from restricted rotation around a single bond, are atropisomers. Due to the unique nature of origins their chirality, synthetic strategies access these compounds in an enantioselective manner differ those used prepare enantioenriched containing point arising unsymmetrically substituted carbon center. In particular stereodynamic transformations, such as dynamic kinetic resolutions, thermodynamic and deracemizations, which rely on ability racemize or interconvert enantiomers, promising set transformations optically pure late stage sequence. Translation approaches with atropisomers requires expanded toolbox for epimerization/racemization provides opportunity develop new conceptual framework synthesis compounds.

Language: Английский

Citations

52
Mechanistic Investigation of Ni-Catalyzed Reductive Cross-Coupling of Alkenyl and Benzyl Electrophiles DOI Creative Commons
Raymond F. Turro, Julie L. Hofstra Wahlman, Zhengjia Tong

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(27), P. 14705 - 14715

Published: June 26, 2023

Mechanistic investigations of the Ni-catalyzed asymmetric reductive alkenylation

Language: Английский

Citations

49
Zinc-free, Scalable Reductive Cross-Electrophile Coupling Driven by Electrochemistry in an Undivided Cell DOI
Mareena C. Franke,

Victoria Longley,

Mohammad Rafiee

et al.

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(20), P. 12617 - 12626

Published: Oct. 3, 2022

Nickel-catalyzed reductive cross-electrophile coupling reactions are becoming increasingly important in organic synthesis, but application at scale is limited by three interconnected challenges: a reliance on amide solvents (complicated workup, regulated), the generation of stoichiometric Zn salts isolation, waste disposal issue), and mixing/activation challenges zinc powder. We show here an electrochemical approach that addresses these issues: reaction works acetonitrile with diisopropylethylamine as terminal reductant simple undivided cell (graphite(+)/nickel foam(-)). The utilizes combination two ligands, 4,4'-di-

Language: Английский

Citations

66
Collaboration as a Key to Advance Capabilities for Earth-Abundant Metal Catalysis DOI
Paul J. Chirik, Keary M. Engle, Eric M. Simmons

et al.

Organic Process Research & Development, Journal Year: 2023, Volume and Issue: 27(7), P. 1160 - 1184

Published: March 20, 2023

Earth-abundant metal (EAM) catalysis can have profound impact in the pharmaceutical industry terms of sustainability and cost improvements from replacing precious metals like palladium as well harnessing differential reactivity first-row that allows for novel transformations to enable more efficient routes clinical candidates. The strategy building these capabilities within process group at Bristol Myers Squibb is described herein, with general plan a reaction screening platform, demonstrating scalability, increasing mechanistic understanding catalyst activation. development catalytic utilizing nickel, cobalt, iron while highlighting importance collaboration internal external groups advance EAM our portfolio. challenges benefits working transition metals, including metrics implementation catalysis, such cost, mass intensity, commercial availability catalysts ligands, are discussed.

Language: Английский

Citations

42
Zinc and manganese redox potentials in organic solvents and their influence on nickel-catalysed cross-electrophile coupling DOI
Zhi-Ming Su, Ruohan Deng, Shannon S. Stahl

et al.

Nature Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 6, 2024

Language: Английский

Citations

14
Effect of 6,6′-Substituents on Bipyridine-Ligated Ni Catalysts for Cross-Electrophile Coupling DOI

Haotian Huang,

Jose L. Alvarez-Hernandez, Nilay Hazari

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(9), P. 6897 - 6914

Published: April 19, 2024

A family of 4,4′-tBu2-2,2′-bipyridine (tBubpy) ligands with substituents in either the 6-position, 4,4′-tBu2-6-Me-bpy (tBubpyMe), or 6 and 6′-positions, 4,4′-tBu2-6,6′-R2-bpy (tBubpyR2; R = Me, iPr, sBu, Ph, Mes), was synthesized. These were used to prepare Ni complexes 0, I, II oxidation states. We observed that 6′-positions tBubpy ligand impact properties complexes. For example, bulkier 6,6′-positions better stabilized (tBubpyR2)NiICl species resulted a cleaner reduction from (tBubpyR2)NiIICl2. However, hindered prevented coordination tBubpyR2 Ni0(cod)2. In addition, by using type (tBubpyMe)NiCl2 (tBubpyR2)NiCl2 as precatalysts for different XEC reactions, we demonstrated 6,6′-substituents lead major differences catalytic performance. Specifically, while (tBubpyMe)NiIICl2 is one most active catalysts reported date can facilitate reactions at room temperature, lower turnover frequencies containing ligands. detailed study on intermediates (tBubpy)Ni(Ar)I (tBubpyMe2)Ni(Ar)I revealed several factors likely contributed activity. whereas are low spin relatively stable, high-spin less stable. Furthermore, captures primary benzylic alkyl radicals more slowly than (tBubpy)Ni(Ar)I, consistent activity former catalysis. Our findings will assist design tailor-made Ni-catalyzed transformations.

Language: Английский

Citations

9
Aryl halide cross-coupling via formate-mediated transfer hydrogenation DOI
Yoon Cho, Yu-Hsiang Chang, Kevin P. Quirion

et al.

Nature Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: March 11, 2025

Language: Английский

Citations

1
Nickel-Catalyzed Inter- and Intramolecular Reductive Cross-Coupling Reactions of Arylbenzylammonium Salts through Highly Site-Selective C–N Bond Cleavage DOI

Ren-Gui Tian,

Longyu Wang,

Linze Zheng

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(7), P. 5039 - 5046

Published: March 20, 2024

The site selectivity has been investigated for the C–N bond cleavage of arylbenzylammonium salts in reductive cross-coupling reactions with carbon electrophiles. A wide variety triflates participated nickel-catalyzed zinc-mediated benzyl–aryl cross-electrophile coupling aryl bromides to afford diarylmethanes extremely high selectivity. same reaction conditions were successfully extended intramolecular benzyl(bromoaryl)ammonium triflates. Moreover, underwent manganese-mediated benzyl–acyl aromatic carboxylic acids presence di-tert-butyl pyrocarbonate. These employ readily available feedstocks and reagents, exhibit benzylic bonds rather than bonds, tolerate a functional groups.

Language: Английский

Citations

6
Cyclopropanation with Non-Stabilized Carbenes via Ketyl Radicals DOI
Duong T. Ngo, Jacob J. A. Garwood, David A. Nagib

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(34), P. 24009 - 24015

Published: July 25, 2024

A radical mechanism enables simple and robust access to nonstabilized, alkyl iron carbenes for novel (2 + 1) cycloadditions. This Fe-catalyzed strategy employs simple, aliphatic aldehydes as carbene precursors in a practical, efficient, stereoselective cyclopropanation. air- water-tolerant method permits convenient generation of coupling an exceptionally wide range sterically electronically diverse alkenes (nucleophilic, electrophilic, neutral). transient ketyl intermediate is key accessing harnessing this rare, reactivity. Mechanistic experiments confirm the (a) intermediacy radicals, (b) formation by capture, (c) nonconcerted nature cycloaddition.

Language: Английский

Citations

6