Applications of Transition Metal-Catalyzed ortho-Fluorine-Directed C–H Functionalization of (Poly)fluoroarenes in Organic Synthesis

Chemical Reviews, Год журнала: 2024, Номер 124(8), С. 4822 - 4862

Опубликована: Апрель 2, 2024

The synthesis of organic compounds efficiently via fewer steps but in higher yields is desirable as this reduces energy and reagent use, waste production, thus environmental impact well cost. reactivity C–H bonds ortho to fluorine substituents (poly)fluoroarenes with metal centers enhanced relative meta para positions. Thus, direct functionalization without prefunctionalization becoming a significant area research chemistry. Novel selective methodologies functionalize (poly)fluorinated arenes by taking advantage the C–F are continuously being developed. This review summarizes reasons for consequent developments valuable (poly)fluoroarene-containing compounds.

Язык: Английский

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Site-Selectivity of C(sp²)–H Oxidative Addition of Fluorinated Arenes with Pyridine(dicarbene) Cobalt(I) Complexes and Aryl Isomerization

Organometallics, Год журнала: 2025, Номер unknown

Опубликована: Март 26, 2025

The rate, site-selectivity, and product isomerization of the C(sp2)–H oxidative addition arenes with pyridine(dicarbene) cobalt methyl phenyl complexes have been investigated four representative varying electronic steric properties. rates activation to yield cobalt-aryl products subsequent aryl were influenced by properties arene; relatively electron-poor arene 3-fluorobenzotrifluoride underwent more than 70 times faster electron-rich substrate, 3-fluoro-N,N,α-trimethylbenzeneacetamide. In all cases, meta-to-fluorine was major at low conversion, which subsequently isomerized ortho isomer over time. Deuterium-labeling experiments measurement methane isotopologues establish that early conversion arises from kinetically preferred, meta-selective addition. Density functional theory calculations support pathways involving cobalt(I)–(III) redox cycles cobalt(I) occurring a high barrier followed reductive elimination. Despite strong σ-donating pincer ligand, π-accepting character carbene donors lowers for elimination, hence, cobalt(III) intermediates not observed.

Язык: Английский

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Well-Defined Low-Valent Cobalt Complexes in Catalysis: An Overview

Organometallics, Год журнала: 2024, Номер 43(9), С. 895 - 923

Опубликована: Апрель 18, 2024

For decades, transition-metal catalysts based on noble metals have proven to be highly efficient for a wide range of organic transformations. However, due their low abundance and volatile price the use such is now critical economy. Thus, more sustainable alternatives mandatory abundant first-row transition are becoming interesting challengers. Among them low-valent 3d appeared as best candidates, they intrinsically reactive than high-valent ones. this reactivity implies that these complexes often generated in situ, putting further away aspect atom economy waste. To circumvent get insight mechanism reaction, concept well-defined has emerged. In area, its historic development trouble associated with preparation other complexes, cobalt appears an important player. review, after definition what complex presentation (pre)catalyst also known "single-component" strategy we will report syntheses applications catalysis classified by oxidation state ligand environment.

Язык: Английский

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Engineering Frustrated Lewis Pair Active Sites in Porous Organic Scaffolds for Catalytic CO₂ Hydrogenation

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(23), С. 15806 - 15814

Опубликована: Май 30, 2024

Frustrated Lewis pairs (FLPs), featuring reactive combinations of acids and bases, have been utilized for myriad metal-free homogeneous catalytic processes. Immobilizing the active sites to a solid support, especially porous scaffolds, has shown great potential ameliorate FLP catalysis by circumventing some its inherent drawbacks, such as poor product separation catalyst recyclability. Nevertheless, designing immobilized pair (LPASs) is challenging due requirement placing donor acceptor centers in appropriate geometric arrangements while maintaining necessary chemical environment perform catalysis, clear design rules not yet established. In this work, we formulate simple guidelines build highly LPASs direct hydrogenation CO2 through large-scale screening diverse library 25,000 FLPs. The built introducing boron-containing acidic vicinity existing basic nitrogen organic linkers metal–organic frameworks collected "top-down" fashion from CoRE MOF 2019 database. geometrical appropriateness these determined evaluating series descriptors representing intrinsic strength (acidity basicity) components their spatial arrangement sites. Analysis leading candidates enables formulation pragmatic experimentally relevant principles which constitute starting point further exploration FLP-based catalysts reduction CO2.

Язык: Английский

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Crystal structure and Hirshfeld-surface analysis of the pesticide etoxazole

Acta Crystallographica Section E Crystallographic Communications, Год журнала: 2025, Номер 81(3), С. 239 - 242

Опубликована: Фев. 18, 2025

Etoxazole (C 21 H 23 F 2 NO ), systematic name 4-(4- tert -butyl-2-ethoxyphenyl)-2-(2,6-difluorophenyl)-4,5-dihydro-1,3-oxazole, is a fluorinated insecticide and acaricide that inhibits chitin biosynthesis, disrupting insect development by preventing proper exoskeleton formation. Widely used in agriculture since 1998, it readily absorbed plant tissues translocates within leaves. Metabolic studies have identified several oxidative degradation products, while toxicological assessments examined potential effects, including stress. This study presents detailed crystallographic Hirshfeld surface analysis of etoxazole. The molecule consists central dihydro-oxazole ring flanked 2,6-difluorophenyl 4- -butyl-2-ethoxyphenyl groups, each twisted relative to the oxazole core. nearly planar, with substituted phenyl rings forming dihedral angles 44.20 (4)° 47.87 mean plane dihydro-oxazole. ethoxy group exhibits angle 15.04 (11)° -butylphenyl ring, -butyl itself shows minor torsional disorder [major:minor occupancies are 0.760 (6):0.240 (6)]. molecular packing dominated van der Waals-type interactions, though weak C—H...F C—H...O interactions lead pleated layers parallel ab plane, which further stack along c -axis direction. A confirms prevalence Waals crystal stabilization.

Язык: Английский

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In-situ reconstruction of electrocatalysts for efficient energy and environmental electrocatalytic reactions

Materials Science and Engineering R Reports, Год журнала: 2025, Номер 164, С. 100978 - 100978

Опубликована: Март 23, 2025

Язык: Английский

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The Role of Boron Reagents in Determining the Site-Selectivity of Pyridine(dicarbene) Cobalt-Catalyzed C–H Borylation of Fluorinated Arenes

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Апрель 17, 2025

The origin of the meta- and ortho-to-fluorine site-selectivity in C(sp2)-H borylation fluorinated arenes with B2Pin2 HBPin promoted by pyridine(dicarbene)cobalt catalysts has been investigated. In situ generation cobalt(I)-boryl complex treatment three representative fluoroarenes established meta-selective oxidative addition to form predominantly meta isomers corresponding cobalt(I)-aryl complexes. Attempts observe or isolate four-coordinate yielded cobalt-hydride dimer, [(iPrACNC)CoH]2, borohydride (iPrACNC)CoH2BPin, diboryl hydride, (iPrACNC)CoH(BPin)2 depending on amounts present. phosphite derivatives (iPrACNC)CoH(P(OiPr)3) (iPrACNC)CoBPin(P(OiPr)3) were prepared crystallographically characterized. catalytic 1,3-difluorobenzene, complexes identified as resting states despite meta-to-fluorine being major product catalysis. Deuterium kinetic isotope effects support irreversible but not turnover-limiting addition. Stoichiometric isolated intermediates that meta-cobalt(I)-aryl was more reactive than ortho-isomer accounts for observed states. All compounds reacted quickly HBPin. While ortho-cobalt(I)-aryl arylboronate products high site-selectivity, meta-cobalt-aryl counterparts a mixture free arene. labeling experiments DBPin confirmed mediates reversible Thus, overall arises from two reinforcing effects: (i) kinetically (ii) faster reaction isomer B2Pin2. As is converted HBPin, reductive elimination competes against isomer, resulting increased ortho-selective borylation.

Язык: Английский

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Cobalt-Catalyzed Cross-Coupling of Glycosyl Sulfones with Zinc reagents toward the Stereoselective Synthesis of C(sp/sp²)-Glycosides

Organic Letters, Год журнала: 2025, Номер unknown

Опубликована: Апрель 18, 2025

A cobalt-catalyzed desulfonylative cross-coupling of glycosyl sulfones with organozinc reagents toward the stereoselective synthesis C-glycosides is reported. The new C-glycoside proceeds under mild reaction conditions and exhibits tolerance to a range functional groups. Diverse alkynylated, arylated, alkenylated products are formed high efficiency excellent diastereoselectivity. Mechanistic studies indicate radical pathway.

Язык: Английский

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Multicomponent Cross-Dehydrogenative Coupling of Imidazo[1,2-a]pyridine: Access to Abnormal Mannich and Mannich-Type Reaction

The Journal of Organic Chemistry, Год журнала: 2024, Номер 89(15), С. 10773 - 10784

Опубликована: Июль 17, 2024

This study showcases successfully switchable approaches to accomplish the C3-aryl methylation and C3- amino of privileged nitrogen-containing pharmaceutical compounds "imidazopyridines" with distinct amines, which surmounts long-standing requirement for a superfluous directing group. These two transformations manifest pronounced regio- chemo-divergent behavior, demonstrating unprecedented multicomponent "abnormal Mannich Mannich-type" reactions. The remarkable environmentally benign protocol has been efficiently extended concise synthesis late-stage derivatization.

Язык: Английский

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Migratory Aryl Cross-Coupling

Journal of the American Chemical Society, Год журнала: 2024, Номер unknown

Опубликована: Дек. 18, 2024

A fundamental property of cross-coupling reactions is regiospecificity, meaning that the site bond formation determined by leaving group's location on electrophile. Typically, achieving a different substitution pattern requires synthesis new, corresponding starting-material isomer. As an alternative, we proposed development variants would afford access to multiple structural isomers from same coupling partners. Here, first demonstrate bulky palladium catalyst can facilitate efficient, reversible transposition aryl halides temporarily forming metal aryne species. Despite nearly thermoneutral equilibrium governing this process, combining it with gradual addition suitable nucleophile results in dynamic kinetic resolution isomeric intermediates and high yields unconventional product isomers. The method accommodates range oxygen- nitrogen-centered nucleophiles tolerates numerous common functional groups. Curtin–Hammett scheme supported computational experimental data, providing general mechanistic framework for extending migratory concept.

Язык: Английский

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