Photochemical and electrochemical strategies in C–F bond activation and functionalization

Organic Chemistry Frontiers, Год журнала: 2021, Номер 9(3), С. 853 - 873

Опубликована: Дек. 7, 2021

The recent advances in photochemical or electrochemical C–F bond activation and functionalization have been summarized discussed.

Язык: Английский

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Radical-Polar Crossover Enabled Triple Cleavage of CF₂Br₂: A Multicomponent Tandem Cyclization to 3-Fluoropyrazoles

Organic Letters, Год журнала: 2023, Номер 25(32), С. 6062 - 6066

Опубликована: Авг. 8, 2023

The elaboration of step-economy and catalytic approaches for accessing diverse fluorinated heterocyclics is highly desirable. Described herein a radical-polar crossover enabled three-component cyclization to polysubstituted fluoropyrazoles by using CF2Br2 as novel C1F1 synthon. Mechanistic experiments revealed that the in situ generation reactive intermediate gem-difluorovinylimine ion key this transformation. This protocol unlocks reactivity adds significant synthetic values fluorine chemistry.

Язык: Английский

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Unconventional Transformations of Difluorocarbene with Amines and Ethers

Accounts of Chemical Research, Год журнала: 2023, Номер 56(5), С. 592 - 607

Опубликована: Фев. 9, 2023

ConspectusFluorine-containing compounds are extensively involved in various fields originating from intriguing and unique characteristics of fluorine atom; notably, pharmaceuticals, the involvement a atom or fluorine-containing group is chief technique for improving pesticide effect developing new drugs. Difluorocarbene, one most important powerful reagents, widely employed studied many areas mainly to assemble gem-difluoromethyl molecules, including but not limited abundant reactions between difluorocarbene with nucleophilic substrates, Wittig reaction ketones aldehydes, cascade both nucleophile an electrophile, [2+1] cycloaddition alkenes alkynes. However, its unconventional protocols beyond as difluoromethyl synthon have rarely been studied, thus, it highly desired given abundance, inexpensiveness peculiar properties. In this Account, we discuss our discovery transformations difluorocarbene, instead sole source (different other dihalocarbene), actually can serve electron acceptor activate C-X bonds (X = N O) thus promote myriad fascinating assembly versatile valuable products aza-compounds (primary/secondary/tertiary amines well NH3 NaNH2 so on) aliphatic ethers absence transition metals expensive ligands. Inspired by electron-deficient first found that isocyanides could be readily formed situ when unoccupied orbital meets lone-pair primary amines; basic condition, defluorination cyclizations afford plethora N-containing heterocycles. Meanwhile, disclosed cyano anion accessible were mixed up suitable conditions, series aryl nitrile obtained presence Pd catalysis ArI. Interestingly, encountered secondary amines, formamides rendered under mild reactions. Of note, concomitant functionalizations C moieties via cleavage unstrained C(sp3)-N bond metal oxidant sparce, which indeed significantly add versatility diversity products. Gratifyingly, uitilizing cyclic tertiary achieved difluorocarbene-mediated deconstructive time, showing successive scission simultaneous functionalization atoms would introduced into oxidants. This method provides brand-new while very universal synthetic pathway selectively cleave inert unactivated Csp3-N bonds, halodifluoromethyl reagents act C1 halo (Cl, Br, I) sources. Fascinatingly, nitrogen ylides generated approach deaminative arylation alkenylation was time appropriate represents mode lead formal transition-metal free Suzuki cross coupling. Besides, also proceed novel recombination render meaningful 2-fluoroindoles 3-(2,2-difluoroethyl)-2-fluoroindoles ortho-vinylanilines, 3-fluorined oxindoles 2-aminoarylketones, acts F1 simultaneously. Last least, recently lone-pair-electron oxygen trap form oxonium ylide, eventually leads C-O formation ethers.

Язык: Английский

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Synthetic Advantages of Defluorinative C−F Bond Functionalization

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(49)

Опубликована: Авг. 22, 2023

Abstract Much progress has been made in the development of methods to both create compounds that contain C−F bonds and functionalize bonds. As such, are becoming common versatile synthetic functional handles. This review summarizes advantages defluorinative functionalization reactions for small molecule synthesis. The coverage is organized by type carbon framework fluorine attached mono‐ polyfluorinated motifs. main challenges, opportunities advances discussed each class organofluorine. Most text focuses on case studies illustrate how defluorofunctionalization can improve routes targets or properties enable unique mechanisms reactions. broader goal showcase incorporating exploiting design routes, improvement specific advent new methods.

Язык: Английский

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Electrochemical radical-polar crossover: a radical approach to polar chemistry

Science China Chemistry, Год журнала: 2023, Номер 67(2), С. 450 - 470

Опубликована: Ноя. 3, 2023

Язык: Английский

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Recent Advances in the Electrochemical Defluorinative Transformations of C—F Bonds

Chinese Journal of Chemistry, Год журнала: 2024, Номер 42(16), С. 1913 - 1928

Опубликована: Апрель 24, 2024

Comprehensive Summary Organic fluorine compounds are ubiquitous and pivotally important organic molecules, yet their activation transformation have long been a formidable challenge due to the high energy low reactivity of C—F bonds. electrosynthesis, an environmentally benign synthetic method in chemistry, enables myriad chemical transformations without need for external redox reagents. In recent years, electrochemistry has emerged as powerful tool achieving bonds fluorine‐containing compounds. This review aims succinctly recapitulate latest advancements electrochemical defluorinative delve into reaction design, mechanistic insights, developmental prospects these methods. Key Scientists 1959, Lund was first pioneer electroreduction CF 3 CH group. Electrochemistry lately provided new opportunities efficient conversion fluorides. 2020, Zhou coworkers discovered carboxylation α‐CF alkenes. Lambert colleagues reported electrophotocatalytic amination aryl Electrochemical hydrodefluorination trifluoromethylketones developed by Lennox 2021. same year, Wang Guo disclosed radical alkylation alkenes with Katritzky salts alkyl precursors. Subsequently, Wu Liao described transition‐metal‐free, site‐selective arylation polyfluoroarenes (het)arenes using paired electrophotocatalysis. 2023, numerous efforts were made achieve bond activation. Xia organoboron‐controlled chemoselective sequential (deutero)hydrodefluorination trifluoroacetamides.

Язык: Английский

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A review of frustrated Lewis pair enabled monoselective C–F bond activation

Chemical Science, Год журнала: 2024, Номер 15(8), С. 2712 - 2724

Опубликована: Янв. 1, 2024

Frustrated Lewis pair (FLP) bond activation chemistry has greatly developed over the last two decades since seminal report of metal-free reversible hydrogen activation. Recently, FLP systems have been utilized to allow monoselective C-F (at equivalent sites) in polyfluoroalkanes. The problem 'over-defluorination' functionalization polyfluoroalkanes (where multiple fluoro-positions are uncontrollably functionalized) a long-standing chemical fluorocarbon for 80 years. mediated is complementary other solutions address and offers several advantages unique opportunities. This perspective highlights some these opportunities places development into context wider effort overcome 'over-defluorination'.

Язык: Английский

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Defluorinative Alkylation of Trifluoromethylbenzimidazoles Enabled by Spin-Center Shift: A Synergistic Photocatalysis/Thiol Catalysis Process with CO₂^•–

Organic Letters, Год журнала: 2022, Номер 24(22), С. 4075 - 4080

Опубликована: Июнь 1, 2022

We describe a catalytic strategy for direct single C(sp3)-F bond alkylation of trifluoromethylbenzimidazoles under photoinduced thiol catalysis process. The CO2 radical anion (CO2•-) proved to be the most efficient single-electron reductant realize such transformation. spin-center shift generated intermediate is key step in realizing C-F activation mild conditions with high efficiency.

Язык: Английский

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Multiple-fold C–F bond functionalization for the synthesis of (hetero)cyclic compounds: fluorine as a detachable chemical handle

Organic Chemistry Frontiers, Год журнала: 2022, Номер 9(7), С. 2013 - 2055

Опубликована: Янв. 1, 2022

We highlighted the recent advances in field of multiple-fold C–F bond functionalization for synthesis (hetero)cyclic compounds.

Язык: Английский

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Ni-Catalyzed Radical-Promoted Defluoroalkylborylation of Trifluoromethyl Alkenes To Access gem-Difluorohomoallylic Boronates

Organic Letters, Год журнала: 2022, Номер 24(12), С. 2446 - 2451

Опубликована: Март 21, 2022

gem-Difluoroalkenyl boronates are attractive synthons for constructing diverse gem-difluoroalkenes and organoboron compounds. However, the strategies construction of gem-difluorohomoallyl has scarcely been described. Herein, we develop an efficient protocol gem-difluorohomoallylic through a Ni-catalyzed radical-promoted defluoroalkylborylation α-trifluoromethyl alkenes with α-haloboronates under mild conditions. This reaction features broad substrate scope good functional group tolerance transformations.

Язык: Английский

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