Mechanistic Study of the Role of Substrate Steric Effects and Aniline Inhibition on the Bis(trineopentylphosphine)palladium(0)-Catalyzed Arylation of Aniline Derivatives

Hu, Huaiyuan; Qu, Fengrui; Gerlach, Deidra L.; Shaughnessy, Kevin H.

doi:10.1021/acscatal.7b00024

Cited by 24 publications

(43 citation statements)

References 55 publications

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“…Our group reported one of the first examples of the use of an oxidative addition complex as a precatalyst species . [(TNpP)Pd(Ar)Br] 2 (TNpP=trineopentylphosphine) complexes afford high rates for the B‐H coupling of sterically hindered aryl bromides and aniline derivatives.…”

Section: Palladium Precatalystsmentioning

confidence: 99%

Development of Palladium Precatalysts that Efficiently Generate LPd(0) Active Species

Shaughnessy

2019

Israel Journal of Chemistry

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Palladium catalysts have become central to modern organic synthesis, particularly in the context of crosscoupling reactions to form CÀ C and C-heteroatom bonds. The development of highly efficient catalyst systems has seen a transition from the use of in situ-generated catalysts derived from a ligand source and palladium precursor to the use of preformed palladium-ligand complexes that can efficiently generate the active species. The design of these systems has focused on optimizing the generation of the LPd(0) species presumed to be the active catalysts with most state-of-the-art ligand systems. This review will highlight the development of Pd(0), Pd(I), and Pd(II) precatalysts that efficiently generate LPd(0) active species with a focus on their activation mechanisms and applications in catalysis. Scheme 3. Synthesis of diene-stabilized LPd(0).Scheme 4. COD-stabilized LPd(0) and application to fluorination reactions. Scheme 14. Activation routes for Pd(allyl) precatalysts. Scheme 15. Competition between formation of active species and inactive μ-allyl palladium(I) dimers.

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Section: Palladium Precatalystsmentioning

confidence: 99%

Development of Palladium Precatalysts that Efficiently Generate LPd(0) Active Species

Shaughnessy

2019

Israel Journal of Chemistry

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“…In 2017, Shaughnessy and co-workers reported a mechanistic study of the Pd/PNp 3 (Np = neopentyl) catalyzed coupling of steric bulky aryl halides and aniline derivatives. 13 The oxidative addition step was found not to be the rate-limiting step when hindered aryl bromides were coupled with hindered aniline derivatives. Unlike the usual cross-coupling of privileged substrates, the ligand geometry appears to be more influential when the coupling partners become more sterically congested.…”

Section: Figure 1 Examples Of Useful Materials With a Sterically Demamentioning

confidence: 96%

“…Spectra were referenced internally to the residual proton resonance in CDCl 3 ( = 7.26) or with TMS ( = 0.00) as the internal standard. 13 C NMR spectra were recorded on a 100 or 125 MHz spectrometer and the spectra were referenced to CDCl 3 ( = 77.0, the middle peak). 31 P NMR spectra were referenced to 85% H 3 PO 4 externally.…”

Section: Special Topic Syn Thesismentioning

confidence: 99%

“…1 H NMR (500 MHz, CDCl 3 ):  = 7.34-7.31 (t, J = 7.5 Hz, 2 H), 7.09-7.06 (t, J = 7.0 Hz, 1 H), 6.99 (d,J = 8.0 Hz,4 H), (t, J = 7.0 Hz, 1 H), 6.72 (s, 2 H), 4.74 (s, 1 H), 2.04 (d,J = 4.5 Hz,12 H). 13 C NMR (125 MHz, CDCl 3 ):  = 158. 3, 151.6, 142.2, 137.6, 132.8, 129.7, 129.1, 129.0, 128.1, 122.5, 121.1, 120.9, 119.5, 119.3, 118.0, 117.9, 19.3, 19.3, 19.2, 19.2…”

Section: N-(26-dimethylphenyl)-26-dimethyl-4-phenoxyaniline (3da)mentioning

confidence: 99%

“…13-1.11 (m, 18 H). 13 C NMR (125 MHz, CDCl 3 ):  = 141. 6, 139.7, 139.5, 137.2, 134.0, 126.3, 123.6, 123.0, 28.4, 27.8, 24.9, 23.6, 16.0, 14. 6, 141.7, 141.0, 139.8, 138.0, 123.8, 121.9, 121.6, 34.0, 27.9, 27.7, 24.3, 23.7, 23.6.…”

Section: N-(26-diisopropylphenyl)-246-triethylaniline (3fd)mentioning

confidence: 99%

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Sterically Hindered Amination of Aryl Chlorides Catalyzed by a New Carbazolyl-Derived P,N-Ligand-Composed Palladium Complex

Lai¹,

Leung²,

Choy³

et al. 2019

Synthesis

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Table of Contents 1. Characterization data of carbazolyl phosphine ligands L2-L4…………………………………. S22. X-ray data of L4 ……………………………………………………………………………………………………… S73. X-ray data of product 6 in Scheme 4………………………………………………………………………… S17 4. 1 H, 13 C and 31 P NMR spectra …………………………………………………………………………………… S28 References………………………………………………………………………………………………………………. S57Supporting Information S2 Characterization data of carbazolyl phosphine ligands L2-L4 General Procedures for Ligand-free Cu-catalyzed amination:Substituted carbazole (40 mmol), CuI (40 mmol, 7.62 g), K2CO3 (80 mmol, 11.0 g) andTeflon-coated magnetic stirrer bar were charged to a two-necked round bottom flask equipped with a condenser and fitted with a septum. The system was carefully evacuated and backfilled with nitrogen (3 cycles). 1,2-Dibromobenzene (80 mmol, 9.65 mL) and distilled dry xylene (130 mL) were added by syringe via septum. The reaction mixture was allowed to reflux in a heating mantle/ preheated oil bath (185 ℃) for 3-7 days. After completion of reaction, the solution was filtered through Celite to remove the copper powder and the xylene was removed by distillation under high vacuum. The crude products (ligand precursor) were purified by flash column chromatography on silica gel (230-400 mesh) to afford the product as a white solid. General Procedures for nucleophilic phosphination:The ligand precursor obtained (5 mmol) was then dissolved in freshly distilled THF (25 mL) at room temperature under nitrogen. The solution was cooled to -78 ℃ in a dry ice/ acetone bath. Titrated n-BuLi (5.5 mmol) was added dropwise with a syringe, and the reaction mixture was stirred for 30 min at -78 ℃. Chlorodicyclohexylphosphine (6 mmol, 1.32 mL) was then added dropwise to the reaction mixture with a syringe. The reaction mixture was warmed to room temperature and stirred for 12 h. The solvent was then removed under reduced pressure. Methanol (10 mL) was added to the residue, and the Supporting Information S3 mixture was stirred at 1250 rpm for 10 min. The white solid product was successively filtered and washed with cold methanol. The white solid was collected and dried over vacuum to afford the carbazolyl-based phosphine ligands. 9-(2-(Dicyclohexylphosphino)phenyl)-3,6-dimethoxy-9H-carbazole (L2) Sodium (200 mmol, 4.6 g) was added in methanol (27 mL) slowly. When all sodium was completely dissolved, distilled dry DMF (107 mL), CuI (40 mmol, 7.62 g) and 3,6dibromocarbazole (10 mmol, 3.25 g) were added. The reaction mixture was allowed to reflux in a preheated oil bath (120 ℃) under nitrogen for 3 hours. After the completion of reaction, ethyl acetate (400 mL) was added and the solution was filtered through Celite to remove the copper powder. The organic layer was extracted with EtOAc, washed with brine. The crude product was purified by flash column chromatography to obtain 3,6dimethoxy-9H-carbazole as yellow solid (62%, 1.41 g). 1 Hexane: EtOAc = 9:1, Rf = 0.23; 1 H NMR (500 MHz, CDCl3) δ 7.77 (s, 1H), 7.50-7.49 (d, J = 2.0 Hz, 2H), 7.32 -7.30 (d, J = 9.0 Hz, 2H)...

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Aromatic Substitution

Crampton¹

2020

Organic Reaction Mechanisms Series

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Mechanistic Study of the Role of Substrate Steric Effects and Aniline Inhibition on the Bis(trineopentylphosphine)palladium(0)-Catalyzed Arylation of Aniline Derivatives

Cited by 24 publications

References 55 publications

Development of Palladium Precatalysts that Efficiently Generate LPd(0) Active Species

Development of Palladium Precatalysts that Efficiently Generate LPd(0) Active Species

Sterically Hindered Amination of Aryl Chlorides Catalyzed by a New Carbazolyl-Derived P,N-Ligand-Composed Palladium Complex

Aromatic Substitution

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