Nickel‐Catalyzed Heck‐Type Monofluoroacetation of Styrenes for Facile Synthesis of Allylic Fluorides

Wang, Zhenyu; Wan, Jia-Hao; Wang, Gao-Yin; Jin, Ruo-Xing; Lan, Quan; Wang, Xisheng

doi:10.1002/asia.201701655

Cited by 22 publications

(6 citation statements)

References 106 publications

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“…On the other hand, in styrene part, electron deactivating Wang group reacted styrenes with fluoroalkyl iodide in presence of nickel catalysts demonstrating wide range of substrate tolerability, and excellent Estereo selectivity in the product allylic fluorides. [21] Treatment of alkenes 18 and ethyl iodomonofluoroacetate 28 as fluoroalkyl coupling partner in presence of 10 mol% NiI 2 , 20 mol% Davephos, 2 equiv. Na 2 CO 3 , 20 mol% of NaI in methylcyanide solvent yielded the allylic fluorides 29 in moderate to good yields (Scheme 13).…”

Section: Intermolecular Heck Reactionsmentioning

confidence: 99%

Emerging Nickel Catalysis in Heck Reactions: Recent Developments

Bhakta

Ghosh

2020

Adv Synth Catal

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The synthetic application of nickel catalysts in Heck-coupling reactions is quite prominent and noticeable of late in organic synthesis. It shows great interest over the other transition metal catalysts due to its unique characteristic that prepares them more significantly applicable in different fields of synthetic application. The usefulness of nickel-catalysts relies in the fact that they are abundant in nature, relatively less precious and environment friendly. Nickel plays pivotal role in different kind of Heck reactions known such as intramolecular-, intermolecular-, reductive-Heck type reaction producing mainly carbocycles and hetero cycles of biological significance. Carbocyclization or hetero-cyclization reaction occurred under optimized reaction conditions developed and come up with the formation of various structural building blocks of naturally occurring compounds. Via reductive Heck cyclization large membered ring of carbo-or hetero-cyclic system was formed which performed key role as building blocks in pharmaceutical synthesis and bioactive molecule formation. Intermolecular Heck type reactions were comparatively more explored. Silyl-Heck, carbonyl-Heck, and other miscellaneous type reactions were covered up through nickel-catalyzed intermolecular Heck reaction. Asymmetric versions of Heck-coupling reactions are also reported to proceed even with unactivated alkenes, offering molecules having quaternary stereogenic center in a regio-and enantioselective manner. This manuscript intends to cover these entire concepts.

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Section: Intermolecular Heck Reactionsmentioning

confidence: 99%

Emerging Nickel Catalysis in Heck Reactions: Recent Developments

Bhakta

Ghosh

2020

Adv Synth Catal

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“…In 2018, Wang and co-workers reported the nickel-catalyzed monofluoroalkylation of styrenes and dienes with a-fluoro-a-bromo acetates to provide racemic secondary and tertiary allylic fluorides in high yields with moderate-toexcellent E:Z selectivities (Scheme 58). [97] Radical-clock and trapping experiments are consistent with am echanism that proceeds by single-electron reduction of the alkyl halide to an alkyl radical, followed by Giese-type addition to the styrene and oxidation to the resulting allylic fluoride (Scheme 58, bottom).…”

Section: Heck-type Cross Couplings Of A-fluoro Alkyl Halides With Alk...mentioning

confidence: 60%

Transition‐Metal‐Catalyzed Monofluoroalkylation: Strategies for the Synthesis of Alkyl Fluorides by C−C Bond Formation

2021

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Alkyl fluorides modulate the conformation, lipophilicity, metabolic stability, and pKa of compounds containing aliphatic motifs and, therefore, have been valuable for medicinal chemistry. Despite significant research in organofluorine chemistry, the synthesis of alkyl fluorides, especially chiral alkyl fluorides, remains a challenge. Most commonly, alkyl fluorides are prepared by the formation of C−F bonds (fluorination), and numerous strategies for nucleophilic, electrophilic, and radical fluorination have been reported in recent years. Although strategies to access alkyl fluorides by C−C bond formation (monofluoroalkylation) are inherently convergent and complexity‐generating, they have been studied less than methods based on fluorination. This Review provides an overview of recent developments in the synthesis of chiral (enantioenriched or racemic) secondary and tertiary alkyl fluorides by monofluoroalkylation catalyzed by transition‐metal complexes. We expect this contribution will illuminate the potential of monofluoroalkylations to simplify the synthesis of complex alkyl fluorides and suggest further research directions in this growing field.

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“… a In the radical-involved mechanisms, Pd catalysis operates under thermal conditions (100–110 °C) − or under blue LED light irradiation at room temperature; − Ni catalysis operates under thermal conditions. − …”

Section: Main Partmentioning

confidence: 99%

Nickel and Palladium Catalysis: Stronger Demand than Ever

2022

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Key similarities and differences of Pd and Ni in catalytic systems are discussed. Overall, Ni and Pd catalyze a vast number of similar C−C and C−heteroatom bond-forming reactions. However, the smaller atomic radius and lower electronegativity of Ni, as well as the more negative redox potentials of low-valent Ni species, often provide higher reactivity of Ni systems in oxidative addition or insertion reactions and higher persistence of alkyl-Ni intermediates against β-hydrogen elimination, thus enabling activation of more reluctant electrophiles, including alkyl electrophiles. Another key point relates to the higher stability of the open-shell electronic configurations of Ni(I) and Ni(III) compared with Pd(I) and Pd(III). Nickel systems very often involve a number of interconvertible Ni (n+) active species of variable oxidation states (Ni(0), Ni(I), Ni(II), and Ni(III)). In contrast, catalytic reactions involving Pd(I) or Pd(III) active species are still relatively less developed and may require facilitation by special ligands or merging with photo-or electrocatalysis. However, the relatively high redox potentials of Pd (n+) species ensure their facile reduction to Pd (0) species under the assistance of numerous reagents or solvents, providing relatively high concentrations of molecular Pd 1 (0) complexes that can reversibly aggregate into active Pd n clusters and nanoparticles to form a cocktail of interconvertible Pd n (0) active species of various nuclearities (i.e., various values of "n"). Nickel systems involving Ni(0) complexes often require special strong reductants; they are more sensitive to deactivation by air and other oxidizers and, as consequence, often operate at higher catalyst loadings than palladium systems in the same reactions. The ease of activation and relatively high stability of low-valent active Pd species provide high robustness and versatility for palladium catalysis, whereas a variety of Ni oxidation states enables more diverse and uncommon reactivity, albeit requiring higher efforts in the activation and stabilization of nickel catalytic systems. As a point for discussion, we may note that Pd catalytic systems may easily form a "cocktail of particles" of different nuclearities but similar oxidation states (Pd 1 , Pd n , Pd NPs), whereas nickel may behave as a "cocktail of species" in different oxidation states but is less variable in stable nuclearities. Undoubtedly, there is stronger demand than ever not only to develop improved efficient catalysts but also to understand the mechanisms of Pd and Ni catalytic systems.

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Nickel‐Catalyzed Heck‐Type Monofluoroacetation of Styrenes for Facile Synthesis of Allylic Fluorides

Cited by 22 publications

References 106 publications

Emerging Nickel Catalysis in Heck Reactions: Recent Developments

Emerging Nickel Catalysis in Heck Reactions: Recent Developments

Transition‐Metal‐Catalyzed Monofluoroalkylation: Strategies for the Synthesis of Alkyl Fluorides by C−C Bond Formation

Nickel and Palladium Catalysis: Stronger Demand than Ever

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