Towards Catalytic C–H Activation Using Main Group Elements DOI
Andrew McNally

Synlett, Journal Year: 2024, Volume and Issue: 35(08), P. 877 - 882

Published: March 19, 2024

Abstract Catalytic C–H activation reactions are now established as a means to directly transform organic molecules and commonly associated with metals such palladium, rhodium, ruthenium iridium. This Account will describe short number of reports demonstrating that structures containing main group elements can facilitate processes. In particular, boron-based catalysts promote catalytic arene borylation reactions, an emerging approach using phosphenium ions also cleave sp2 bonds. These processes use Lewis acidic atom combined pendant base bonds, which compares metal-catalyzed proceed via concerted metalation deprotonation mechanisms. 1 Introduction 2 Metal-Catalyzed Activation CMD/AMLA Mechanisms 3 Borylation Boron-Based Catalysts 4 Using Phosphenium Ions 5 Conclusions

Language: Английский

Chemo-, regio-, and stereoselective tetrafunctionalization of fluoroalkynes enables divergent synthesis of 5-7-membered azacycles DOI Creative Commons
Jiawei Chen, Wenjun Ji, Xueying Huang

et al.

Chemical Science, Journal Year: 2024, Volume and Issue: 15(30), P. 12026 - 12035

Published: Jan. 1, 2024

A 1,2,3,4-tetrafunctionalization of polyfluoroalkynes for the divergent construction 5-7-membered ( E )-1,2-difluorovinyl azacycles is developed.

Language: Английский

Citations

16
Zirconium-Mediated Carbon-Fluorine Bond Functionalisation Through Cyclohexyne “Umpolung” DOI Creative Commons
Sara Bonfante, Theo F. N. Tanner, Christian Lorber

et al.

Chemical Science, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Polarity reversal, or "umpolung", is a widely acknowledged strategy to allow organic functional groups amenable react in alternative ways the usual preference set by their electronic features. In this article, we demonstrate that cyclohexyne umpolung, realized through complexation zirconocene, makes small strained cycloalkyne C-F bond functionalisation. Such strong activation chemistry unprecedented "free" aryne and alkyne chemistry. Our study also reveals reactivity of Zr-cyclohexyne complex highly sensitive degree fluorination heteroarene. addition, parasitic reactions ancillary ligand PMe3 were observed when pentafluoropyridine was substrate.

Language: Английский

Citations

0
Boron, Aluminum, and Gallium Fluorides as Catalysts for the Defluorofunctionalization of Electron-Deficient Arenes: The Role of NaBArF4 Promoters DOI Creative Commons
Wenbang Yang, Andrew J. P. White, Mark R. Crimmin

et al.

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

Published: March 21, 2025

A series of boron, aluminum, and gallium difluoride complexes [{(ArNCMe)2CH}MF2] (M = B, Al, Ga) are reported as catalysts for the defluorofunctionalization electron-deficient arenes. Thiodefluorination reactions between TMS–SPh poly(fluorinated aromatics) proceed under forcing conditions. Evidence is presented fluoride entering catalytic cycle through a metathesis reaction with to form metal thiolate intermediates, e.g., [{(ArNCMe)2CH}MF(SPh)], which then nucleophiles addition aromatic substrate, likely concerted SNAr mechanism. Attempts expand scope reactivity include hydrodefluorination arenes met limited success. Activity could, however, be recovered NaBArF4 additive (ArF 3,5-C6H3(CF3)2). NMR titrations suggest that capable coordinating aluminum complexes, most weak M–F---Na interactions Ga), can play role in lowering barrier Et3SiH group 13 hydrido [{(ArNCMe)2CH}M(H)F], facilitating turnover. DFT calculations indicate this interaction leads polarization M–F bond. The discovery effect has potentially broad implications developing new applications thermodynamically stable fluorides.

Language: Английский

Citations

0
Surface-Assisted Selective Air Oxidation of Phosphines Adsorbed on Activated Carbon DOI Creative Commons
John C. Hoefler,

Devin Jackson,

Janet Blümel

et al.

Inorganic Chemistry, Journal Year: 2024, Volume and Issue: 63(20), P. 9275 - 9287

Published: May 9, 2024

Trialkyl- and triarylphosphines readily adsorb onto the surface of porous activated carbon (AC) even in absence solvents through van der Waals interactions between lone electron pair AC surface. This process has been proven by solid-state NMR techniques. Subsequently, it is demonstrated that enables fast selective oxidation adsorbed phosphines to phosphine oxides at ambient temperature air. In solution, trialkylphosphines are oxidized a variety P(V) species when exposed atmosphere, while neat or dissolved cannot be with When trialkyl- PnBu3 (1), PEt3, (2), PnOct3 (3), PMetBu2 (4), PCy3 (5), PPh3 (6) mono- submonolayer on AC, solvent temperature, they quantitatively oxides, 1ox–6ox, once air admitted. No formation any unwanted side products water adducts observed. The can then recovered good yields washing them off AC. likely facilitated radical activation molecular oxygen due delocalized electrons aromatic coating as ESR. easy inexpensive method renders hydrogen peroxide other oxidizers unnecessary broadly applicable sterically hindered air-stable triarylphosphines. Phosphines lower coverages oxidize faster rate. All reactions were monitored solution- spectroscopy.

Language: Английский

Citations

3
Transition Metal-Mimicking Relay Catalysis by a Low-Valent Phosphorus Compound DOI

P Sreejyothi,

Nimisha Gautam, Subir Maji

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(24), P. 16743 - 16752

Published: June 6, 2024

Low-valent main group species have been evolving as powerful alternatives to transition metals over the years due their advantages such low toxicity and high abundance. However, inability of elements mimic redox-switching property often limits role catalysts. Here, we demonstrate use a low-valent phosphorus(I) compound an efficient metal-free catalyst for synthesis biologically relevant γ-butyrolactones through dual activation under ambient reaction conditions. The highly nucleophilic center plays key in leading this transformation. Extensive experimental theoretical studies suggest that phosphorus exhibits facile switching between its reduced state [P(I)] oxidized [P(III)] during transformation, mimicking behavior metals.

Language: Английский

Citations

3
Antimony Redox Catalysis: Hydroboration of Disulfides through Unique Sb(I)/Sb(III) Redox Cycling DOI
Minghao Huang, Kunlong Li, Zichen Zhang

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(29), P. 20432 - 20438

Published: July 9, 2024

The stibinidene ArSb

Language: Английский

Citations

3
Ligand Centered Reactivity of a Transition Metal Bound Geometrically Constrained Phosphine DOI Creative Commons

Aaron J. King,

José M. Goicoechea

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(26)

Published: March 4, 2024

The electronic properties, coordination chemistry and reactivity of metal complexes a planar (C

Language: Английский

Citations

2
A Sterically Accessible Monomeric Stibine Oxide Activates Organotetrel(IV) Halides, Including C–F and Si–F Bonds DOI Creative Commons
John S. Wenger, Timothy C. Johnstone

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(28), P. 19350 - 19359

Published: July 3, 2024

Phosphine oxides and arsine are common laboratory reagents with diverse applications that stem from the chemistry exhibited by these monomeric species. Stibine are, in contrast, generally dimeric or oligomeric species because of reactivity-quenching self-association highly polarized stiboryl (Sb=O/Sb+–O–) group. We recently isolated Dipp3SbO (Dipp = 2,6-diisopropylphenyl), first example a kinetically stabilized stibine oxide, which exists as bench-stable solid bears an unperturbed Herein, we report isolation Mes3SbO (Mes mesityl), less bulky substituents maintain nature compound but unlock access to wider range reactivity at group relative Dipp3SbO. was found be potent Lewis base formation adducts main-group acids PbMe3Cl SnMe3Cl. The accessible acidity Sb atom results change GeMe3Cl, SiMe3Cl, CPh3Cl. With species, formally adds E–Cl (E Ge, Si, C) bond across unsaturated form 5-coordinate stiborane. biphilicity is sufficiently activate even C–F Si–F bonds C(p-MeOPh)3F SiEt3F, respectively. These mark significant contribution increasingly rich literature on polar, motifs. Furthermore, highlight utility kinetic stabilization approach unusual bonding motifs unquenched can leveraged for small-molecule activation.

Language: Английский

Citations

2
Transition Metal Mimetic π-Activation by Cationic Bismuth(III) Catalysts for Allylic C–H Functionalization of Olefins Using C═O and C═N Electrophiles DOI Creative Commons

Ruihan Wang,

Sebastián Martínez,

Johannes Schwarzmann

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(32), P. 22122 - 22128

Published: Aug. 5, 2024

The discovery and utilization of main-group element catalysts that behave similarly to transition metal (TM) complexes have become increasingly active areas investigation in recent years. Here, we report a series Lewis acidic bismuth(III) allow for the catalytic allylic C(sp3)–H functionalization olefins via an organometallic complexation-assisted deprotonation mechanism generate products containing new C–C bonds. This heretofore unexplored mode reactivity was applied regioselective 1,4-dienes allylbenzene substrates. Experimental computational mechanistic studies support key steps proposed cycle, including intermediacy elusive Bi–olefin allylbismuth species.

Language: Английский

Citations

2
Synthesis and redox catalysis of Carbodiphosphorane ligated stannylene DOI Creative Commons
Zhuchunguang Liu, Zhijun Wang, Mu Huan

et al.

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: Nov. 14, 2024

Heavier group 14 carbene analogues, exhibiting transition-metal-like behavior, display remarkable capability for small molecule activation and coordination chemistry. However, their application in redox catalysis remains elusive. In this paper, we report the synthesis isolation of a stannylene with carbodiphosphorane ligand. The nucleophilic reactivity at divalent tin center is elucidated by computational studies. Moreover, exhibits catalytic activity hydrodefluorination reaction fluoroarenes. Mechanistic investigations into elementary steps confirm Sn

Language: Английский

Citations

2