Redox-Neutral Organometallic Elementary Steps at Bismuth: Catalytic Synthesis of Aryl Sulfonyl Fluorides

Magre, Marc; Cornellà, Josep

doi:10.1021/jacs.1c11463

Cited by 62 publications

(69 citation statements)

References 71 publications

(44 reference statements)

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“…Inspired by these promising precedents, together with the well-known benign properties associated with Bi, 31 we started a research program capitalizing on the organometallic properties of high- and low-valent Bi complexes, both in redox and nonredox catalysis. 32 Inspired by the sulfone-based bismacyclic scaffolds by Suzuki, 33 our group reported sulfoximine-based Bi compounds capable of forging C(sp 2 )–F bond formation. 32b Specifically, we provided conditions for the stoichiometric and catalytic oxidative fluorination of arylboronic acid derivatives in a redox process .…”

Section: Introductionmentioning

confidence: 99%

Mechanism of the Aryl–F Bond-Forming Step from Bi(V) Fluorides

et al. 2022

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In this article, we describe a combined experimental and theoretical mechanistic investigation of the C(sp 2 )–F bond formation from neutral and cationic high-valent organobismuth(V) fluorides, featuring a dianionic bis-aryl sulfoximine ligand. An exhaustive assessment of the substitution pattern in the ligand, the sulfoximine, and the reactive aryl on neutral triarylbismuth(V) difluorides revealed that formation of dimeric structures in solution promotes facile Ar–F bond formation. Noteworthy, theoretical modeling of reductive elimination from neutral bismuth(V) difluorides agrees with the experimentally determined kinetic and thermodynamic parameters. Moreover, the addition of external fluoride sources leads to inactive octahedral anionic Bi(V) trifluoride salts, which decelerate reductive elimination. On the other hand, a parallel analysis for cationic bismuthonium fluorides revealed the crucial role of tetrafluoroborate anion as fluoride source. Both experimental and theoretical analyses conclude that C–F bond formation occurs through a low-energy five-membered transition-state pathway, where the F anion is delivered to a C(sp 2 ) center, from a BF 4 anion, reminiscent of the Balz–Schiemann reaction. The knowledge gathered throughout the investigation permitted a rational assessment of the key parameters of several ligands, identifying the simple sulfone-based ligand family as an improved system for the stoichiometric and catalytic fluorination of arylboronic acid derivatives.

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Section: Introductionmentioning

confidence: 99%

Mechanism of the Aryl–F Bond-Forming Step from Bi(V) Fluorides

et al. 2022

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“…Our group has recently been interested in the chemistry of organobismuth compounds, from the point of view of both catalysis 18 and structure. 19 Due to the limited number of triarylhalobismuthonium cations and the even more limited structural information, we decided to fill this gap in the area by preparing a family of novel cationic fluorotriarylbismuthonium salts, whose structures were analyzed both in solution (NMR) and in solid state (XRD).…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Structure of Mono-, Di-, and Trinuclear Fluorotriarylbismuthonium Cations

et al. 2022

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A series of cationic fluorotriarylbismuthonium salts bearing differently substituted aryl groups (Ar = 9,9-Me 2 -9H-xanthene, Ph, Mes, and 3,5- t Bu-C 6 H 3 ) have been synthesized and characterized. While the presence of simple phenyl substituents around the Bi center results in a polymeric structure with three Bi centers in the repeating monomer, substituents at the ortho - and meta -positions lead to cationic mono- and dinuclear fluorobismuthonium complexes, respectively. Preparation of all compounds is accomplished by fluoride abstraction from the parent triaryl Bi(V) difluorides using NaBAr F (BAr F – = B[C 6 H 3 -3,5-(CF 3 ) 2 ] 4 – ). Structural parameters were obtained via single crystal X-ray diffraction (XRD), and their behavior in solution was studied by NMR spectroscopy. Trinuclear and binuclear complexes are held together through one bridging fluoride (μ-F) between two Bi(V) centers. In contrast, the presence of Me groups in both ortho -positions of the aryl ring provides the adequate steric encumbrance to isolate a unique mononuclear nonstabilized fluorotriarylbismuthonium cation. This compound features a distorted tetrahedral geometry and is remarkably stable at room temperature both in solution (toluene, benzene and THF) and in the solid state.

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“…While non-redox Bi catalysis has been dominated by Lewis acid catalyzed transformations, redox-neutral Bi(III) catalysis in which a Bi(III) catalyst does not act as a mere Lewis acid has been recently demonstrated in a catalytic synthesis of (hetero)aryl sulfonyl fluorides from (hetero)aryl boronic acids using sulfur dioxide (SO 2 ) and Selectfluor ( 96 ) ( Figure 12 ). 77 A Bi(III) catalyst 92 was found to be an optimal catalyst for this reaction, which was discovered through modification of the diarylsulfone ligands that were used in Bi(III)/Bi(V) redox catalysis. Analogous to the fluorination and the triflation catalysis ( section 3 ), the catalyst 92 readily undergoes transmetallation with a (hetero)aryl boronic acid to generate (hetero)arylbismuthine 94 .…”

Section: Redox-neutral Bi(iii) Catalysismentioning

confidence: 99%

“…Looking ahead, we anticipate numerous opportunities for discovery in bismuth redox catalysis: While other elementary steps (e.g., OA, LM, RE) comprising TM catalysis are analogously realized in Bi catalysis, combinations with migratory insertion-type elementary steps are relatively less explored. 28i , 49b , 77 , 74 Incorporating this type of insertion step into a catalytic cycle would enable new transformations, using small molecules as building blocks. Compared to organo–Bi(I), −Bi(III), and −Bi(V) compounds, open-shell −Bi(0), −Bi(II), and −Bi(IV) species are much less explored or unknown.…”

Section: Conclusion and Future Outlookmentioning

confidence: 99%

Bismuth Redox Catalysis: An Emerging Main-Group Platform for Organic Synthesis

2022

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Bismuth has recently been shown to be able to maneuver between different oxidation states, enabling access to unique redox cycles that can be harnessed in the context of organic synthesis. Indeed, various catalytic Bi redox platforms have been discovered and revealed emerging opportunities in the field of main group redox catalysis. The goal of this perspective is to provide an overview of the synthetic methodologies that have been developed to date, which capitalize on the Bi redox cycling. Recent catalytic methods via low-valent Bi(II)/Bi(III), Bi(I)/Bi(III), and high-valent Bi(III)/Bi(V) redox couples are covered as well as their underlying mechanisms and key intermediates. In addition, we illustrate different design strategies stabilizing low-valent and high-valent bismuth species, and highlight the characteristic reactivity of bismuth complexes, compared to the lighter p -block and d -block elements. Although it is not redox catalysis in nature, we also discuss a recent example of non-Lewis acid, redox-neutral Bi(III) catalysis proceeding through catalytic organometallic steps. We close by discussing opportunities and future directions in this emerging field of catalysis. We hope that this Perspective will provide synthetic chemists with guiding principles for the future development of catalytic transformations employing bismuth.

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Redox-Neutral Organometallic Elementary Steps at Bismuth: Catalytic Synthesis of Aryl Sulfonyl Fluorides

Cited by 62 publications

References 71 publications

Mechanism of the Aryl–F Bond-Forming Step from Bi(V) Fluorides

Mechanism of the Aryl–F Bond-Forming Step from Bi(V) Fluorides

Synthesis and Structure of Mono-, Di-, and Trinuclear Fluorotriarylbismuthonium Cations

Bismuth Redox Catalysis: An Emerging Main-Group Platform for Organic Synthesis

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