Synthesis of Fluorine-Containing 6-Arylpurine Derivatives &lt;i&gt;via&lt;/i&gt; Cp*Co(III)-Catalyzed C–H Bond Activation

Murakami, Nanami; Yoshida, Misaki; Yoshino, Tatsuhiko; Matsunaga, Shigeki

doi:10.1248/cpb.c17-00797

Cited by 35 publications

(15 citation statements)

References 55 publications

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“…[7][8][9][10] In contrast, the catalytic activity of Cp*Co(III) complexes has long been ignored and remained mostly unexplored until recently. The recent upsurge of publications dealing with the use of Cp*Co(III)-catalysts in C-H bond functionalizations [11][12][13][14][15][16] was triggered by the remarkable reports by Kanai and Matsunaga [17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] (scheme 1) and by Ackerman et al [34][35][36][37][38][39][40][41][42][43][44][45] and followed by a number of other reports. 46,47 In many reported cases this powerful class of cobalt catalysts 11 presents reactivity profiles that differ from their rhodium and iridium analogues.…”

Section: Introductionmentioning

confidence: 99%

Making Base-Assisted C–H Bond Activation by Cp*Co(III) Effective: A Noncovalent Interaction-Inclusive Theoretical Insight and Experimental Validation

Deraedt

Cornaton

et al. 2020

Organometallics

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The base-assisted cyclometallation of 2-phenylpyridine (2-phpyH) by Cp*Co(III) was holistically addressed both theoretically and experimentally. Combined DFT and DLPNO-CCSD(T) methods assisted by QTAIM-based noncovalent interactions plots (NCI plots), interacting quantum atoms (IQA), and local energy decomposition (LED) analyses have been used for a comparative study of the CMD-promoted cyclocobaltation and the parent cycloiridation of the 2-phpyH. Results suggest a remarkable contribution of noncovalent interactions, especially local electrostatic interactions, in the evolution of the reactive site giving a rational for the optimization of cyclocobaltation. The theoretically predicted benefits of using the acetamidate anion as a base is rationalized and verified experimentally. Cobaltacycle [Cp*Co(2-phpy-C,N)I] was efficiently synthesized from the air-stable [Cp*CoI2]2 and 2-phpyH, in the presence of LiNHAc as base in 83% yield whereas with anhydrous NaOAc as base only 12% yield were achieved under similar conditions. By applying the [NHAc] -promoted cyclometallation various cobaltacycles were synthesized, analytically characterized and their structures resolved by X-ray crystallization analysis, confirming the importance of the acetamidate in the base-assisted cyclometallation. Experimental kinetic isotope effect (KIE) studies validated by Bigeleisen equation-based KIE computations confirm that the formation of the agostic transient is indeed the kinetic determining step of the CMD mechanism in dichloromethane. Application of the [Cp*CoI2]2/LiNHAc mixture to the catalysis of the condensation of 1,2-diphenyacetylene to various aromatics reveals the coexistence of two mechanisms, i.e. CMD and electrophilic C-H activation. PhD stipend. YC thanks the Centre de Calcul de l'Université de Strasbourg for providing access to the HPC facilities (project g2019a126c).

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Section: Introductionmentioning

confidence: 99%

Making Base-Assisted C–H Bond Activation by Cp*Co(III) Effective: A Noncovalent Interaction-Inclusive Theoretical Insight and Experimental Validation

Deraedt

Cornaton

et al. 2020

Organometallics

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“…[48] Thegroup of Matsunaga and Yoshino reported the Co III -catalyzed C À Hv inylation and allylation of 6-arylpurines. [49] Further cyclization using residual directing groups and introduced fluoroalkenyl moieties enables the construction of heterocycles.T he group of Loh and Feng constructed fivemembered lactams by adouble CÀFbond activation based on…”

Section: à Hb Ond Cleavage-insertionmentioning

confidence: 99%

Transition‐Metal‐Mediated and ‐Catalyzed C−F Bond Activation by Fluorine Elimination

2018

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The activation of carbon-fluorine (C-F) bonds is an important topic in synthetic organic chemistry. Metal-mediated and -catalyzed elimination of β- or α-fluorine proceeds under milder conditions than oxidative addition to C-F bonds. The β- or α-fluorine elimination is initiated from organometallic intermediates having fluorine substituents on carbon atoms β or α to metal centers, respectively. Transformations through these elimination processes (C-F bond cleavage), which are typically preceded by carbon-carbon (or carbon-heteroatom) bond formation, have been increasingly developed in the past five years as C-F bond activation methods. In this Minireview, we summarize the applications of transition-metal-mediated and -catalyzed fluorine elimination to synthetic organic chemistry from a historical perspective with early studies and from a systematic perspective with recent studies.

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“…These reactions exploit a single-component catalyst [Cp*Co(CH 3 CN) 3 ](SbF 6 ) 2 and deliver Z-substituted monofluoroalkenes 112 (Scheme 29). [30] In these reactions, both the N1 and N7 atoms might contribute to the excellent ortho regioselectivity of the reactions.…”

Section: Ortho-directed Cà H/cà F Functionalizationmentioning

confidence: 99%

Recent Advances in Transition Metal‐Catalyzed Functionalization of gem‐Difluoroalkenes

Koley

Altman

2020

Israel Journal of Chemistry

130

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gem-Difluorinated alkenes are readily accessible building blocks that can undergo functionalization to provide a broad spectrum of fluorinated and non-fluorinated products. Herein, we review recent (since 2017) transition metalcatalyzed transformations of these specialized alkenes and summarize general reactivity patterns of these reactions. Many transition metal-catalyzed reactions undergo net CÀ F bond functionalization reactions to deliver monofluorinated products. These reactions typically proceed through β-fluoroalkylmetal intermediates that readily eliminate a βfluoride to deliver monofluoroalkene products. A second series of reactions exploit coinage metal fluorides to add F À to the gem-difluorinated alkene, and further functionalization delivers trifluoromethyl-containing products. In stark contrast, few transition metal-catalyzed reactions proceed in net "fluorine-retentive processes" to deliver difluoromethylenebased products. Reactions Proceeding via β-Fluoride Eliminationgem-Difluoroalkenes react with a variety of transition metalbased catalyst systems (e. g. Cu, Co, Mn, Pd, Ni, Ru, Rh) in net CÀ F functionalization reactions. These reactions typically proceed through a β-fluoroalkylmetal intermediate that readily undergoes β-fluoride elimination to form a new alkene based product (Scheme 1). At first, reaction of a substrate-ligated complex (1) to the gem-difluoroalkene 2, proceeds through a four-membered transition state 3 to generate the intermediate 4. This process involves the matching of the anionic ligand (Y) with the cationic α,α-difluorinated position of the alkene, which generates an intermediate metalalkyl bearnig two βfluoride atoms. Subsequent β-fluoride elimination generates [a] S.Scheme 3. Plausible mechanism for defluoroborylation of aliphatic gem-difluoroalkenes. Scheme 4. CÀ F Bond borylation of gem-difluoroalkenes. Scheme 5. Copper-catalyzed trans-selective monodefluoroborylation of various gem-difluoroalkenes. Scheme 6. CÀ F Bond borylation of gem-difluoroalkenes. Scheme 7. Copper-catalyzed tunable multi-borylation reactions of gem-difluoroalkenes. In parentheses the ratio of 22, 23 and 24 is reported. Scheme 8. Stereoselective defluorinative borylation and silylation of gem-difluoroalkenes. Scheme 9. a) Synthesis of fluorinated vinylsilanes from gem-difluoro/ polyfluoroalkenes. b) Cross-coupling reaction of 29 b and iodobenzene. Scheme 10. Nickel-catalyzed fluoroalkenylation of unactivated alkylbromides. rr = The regioisomeric ratio of the benzylic fluoroÀ alkenylation product to the other regioisomers. DMA = N,N-Dimethylacetamide. Scheme 14. Iron-catalyzed defluorinative cross-coupling of donor alkenes with gem-difluoroalkenes. Dibm = diisobutyrylmethane. Scheme 15. Nickel-catalyzed reductive aryl monofluoroalkenylation of alkenes. Scheme 16. Plausible mechanism for reductive aryl monofluoroalkenylation of gem-difluoroalkenes. Scheme 17. Nickel-catalyzed hydroalkenylation of alkynes through oxidative cyclization and β-fluoride elimination. Scheme 28. Ruthenium-catalyzed fluoroal...

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Synthesis of Fluorine-Containing 6-Arylpurine Derivatives <i>via</i> Cp*Co(III)-Catalyzed C–H Bond Activation

Cited by 35 publications

References 55 publications

Making Base-Assisted C–H Bond Activation by Cp*Co(III) Effective: A Noncovalent Interaction-Inclusive Theoretical Insight and Experimental Validation

Making Base-Assisted C–H Bond Activation by Cp*Co(III) Effective: A Noncovalent Interaction-Inclusive Theoretical Insight and Experimental Validation

Transition‐Metal‐Mediated and ‐Catalyzed C−F Bond Activation by Fluorine Elimination

Recent Advances in Transition Metal‐Catalyzed Functionalization of gem‐Difluoroalkenes

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