Regioselective C–H/C–X activation of naphthyl-derived ligands to form six-membered palladacycles

Anderson, Craig M.; Oh, Nathaniel; Balema, Tedros A.; Mastrocinque, Francesco; Mastrocinque, Claudio; Santos, Danielle das Chagas; Greenberg, Matthew W.; Tanski, Joseph M.

doi:10.1016/j.tetlet.2016.08.092

Cited by 8 publications

(4 citation statements)

References 36 publications

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“…Palladium(0) complexes are the most common catalysts for cross-coupling reactions . According to this, there are a significant number of theoretical and experimental works centered about the oxidative addition of C–X bonds (X = Cl, Br, I) to zerovalent d 10 metal centers . In the past years, examples have appeared where rhodium catalysts enable coupling of haloarenes, whereas other ones have proved to be particularly efficient for dehalogenation reactions .…”

Section: Introductionmentioning

confidence: 99%

Pyridyl-Directed C–H and C–Br Bond Activations Promoted by Dimer Iridium-Olefin Complexes

et al. 2018

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Complexes [Ir(μ-Cl)(η 2-C 8 H 14) 2 ] 2 (1) and [Ir(μ-Cl)(η 4-C 8 H 12)] 2 (2) promote the pyridyl-directed ortho-CH and ortho-CBr activations of the phenyl substituent of 2-(2-bromophenyl)pyridine. The formed products depend upon the olefin of the dimer, which governs the kinetic preference of the activation. The cyclooctene complex 1 reacts with the substituted heterocycle to give (η 2-C 8 H 14) 2 Ir(μ-Cl) 2 Ir{κ 2-C,N-[C 6 BrH 3-py]} 2 (3), in acetone, at room temperature. Treatment of 3 with K(acac) affords Ir(acac)(η 2-C 8 H 14) 2 (4) and Ir(acac){κ 2-C,N-[C 6 BrH 3-py]} 2 (5; acac = acetylacetone). Under more severe conditions, 2-ethoxyethanol under reflux, the reaction of 1 with the heterocycle gives a yellow solid, which yields a 5:82:7 mixture of 5, Ir(acac){κ 2-C,N-[C 6 BrH 3-py]}{κ 2-C,N-[C 6 H 4-py]} (6), and Ir(acac){κ 2-C,N-[C 6 H 4-py]} 2 (7) by reaction with K(acac). In acetone or toluene, at room temperature, 2-(2-bromophenyl)pyridine breaks the chloride bridges of dimer 2 to form IrCl(η 4-C 8 H 12){κ 1-N-[py-C 6 BrH 4 ]} (8), which evolves into IrClBr{κ 2-C,N-[C 6 H 4-py]}(η 4-C 8 H 12) (9) as a result of the oxidative addition of the ortho-CBr of the phenyl substituent to the metal center. Treatment of 9 with Ag 2 O in acetylacetone leads to Ir(acac){κ 2-C,N-[C 6 H 4-py]}{κ 1-C, η 2-[C 8 H 12-(C 3-acac)]} (10), as a consequence of the replacement of the halides by an O,O-chelate acac ligand and the outside to metal nucleophilic attack of a second acac group to the diene C−C double bond disposed trans to bromide.

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Section: Introductionmentioning

confidence: 99%

Pyridyl-Directed C–H and C–Br Bond Activations Promoted by Dimer Iridium-Olefin Complexes

et al. 2018

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“…The bond distances around the Pd( ii ) atom in the aforementioned complexes are comparable with the corresponding distances reported for the related known pincer complexes. 14,28,29,42 The six-membered [Pd{κ 2 ( C , N )}] ring in 6 and 7 revealed a deep boat conformation while that in 3 ½ toluene, 5 ½ toluene ½ pivalic acid revealed a shallow boat conformation as reflected from the values of θ 2 and θ 3 . This feature arises in order to minimise the steric repulsion between two bulkier CF 3 groups of the guanidinate(1−) ligand in 6 and 7 .…”

Section: Resultsmentioning

confidence: 99%

“…complexes. 14,28,29,42 The six-membered [Pd{k 2 (C,N)}] ring in 6 and 7 revealed a deep boat conformation while that in 3 1 2 toluene, 5 1 2 toluene 1 2 pivalic acid revealed a shallow boat conformation as reflected from the values of y 2 and y 3 . This feature arises in order to minimise the steric repulsion between two bulkier CF 3 groups of the guanidinate(1À) ligand in 6 and 7.…”

Section: Njc Papermentioning

confidence: 98%

Guanidine-centred reactivity of CNN Pd(ii) pincer complexes including carboxylate-assisted N–H activation and –CH₂– → –C(O)– oxygenation

Sinha,

Khan,

Sivasankar

et al. 2024

New J. Chem.

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“…Minghetti and co-workers first prepared and structurally characterized [6,5] CNN Pd(II) pincer complex of type C with the objectives aimed at exploring CO insertion into the Pd–C bond . In addition to their structural and catalytic roles, [6,5] CNN Pd(II) pincer complexes have been observed as one of the products of Pd(II) mediated regioselective C–H activation of naphthyl derived bidentate N-donor ligands . Further, [6,5] CNN Pd(II) pincer complexes of the type [Pd{κ 3 ( C , N,N )}(Lewis base)] are often found as one of the key intermediates in Pd(II) catalyzed directed C–H activation reactions …”

Section: Introductionmentioning

confidence: 99%

[6,5] CNN Palladium(II) Pincer Complexes Containing N-Substituted Monoanionic and Dianionic Guanidinate Ligands: Syntheses, Structural Aspects, and Their Utility in Suzuki–Miyaura Coupling Reactions

Sinha

Thirupathi

2021

Organometallics

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The reactions of guanidines [(ArNH)(ArN)CN-(H)(C(O)Py-2)] (Ar = 2-RC 6 H 4 ; R = Me (1) and CF 3 (2)) with Pd(OC(O)R′) 2 (R′ = Me, t Bu and CF 3 ) were studied with a view aimed at understanding the influence of substituent effects upon the nature of the resulting products. The reactions of 1 with Pd(OC(O)R′) 2 (R′ = Me and CF 3 ) in toluene at 65 °C afforded [Pd{κ 3 (C,N,N)}(OC(O)R′)] (R′ = Me (3) and CF 3 (4)), while the analogous reaction involving 1 and Pd(OC(O) t Bu) 2 afforded [Pd{κ 3 (C,N,N)}(μ-OC(O) t Bu)Pd{κ 3 (C,N,N)}] (5). The analogous reactions of 2 with Pd(OC(O)R′) 2 (R′ = Me, t Bu and CF 3 ) afforded [Pd{κ 3 (C,N,N)}(μ-OC(O)R′)Pd{κ 3 (C,N,N)}] (R′ = Me (6) and t Bu (7)) and [Pd{κ 3 (C,N,N)}(OC(O)CF 3 )] (8), respectively. Complexes 5−7 were treated with 2 equiv of Lewis bases, L at RT to afford [Pd{κ 3 (C,N,N)}(L)] [L = PPh 3 (9), 4-aminopyridine (10 and 11), and MeCN (12)]. The mechanisms of formation of new complexes were proposed. Complex 3 was treated with 12 in the presence of excess of NaOC(O) t Bu in CHCl 3 under reflux condition to afford a mixed Pd(II) pincer, [Pd{κ 3 (C,N,N)}(μ-OC(O) t Bu)Pd{κ 3 (C,N,N)}] (15), and this observation indirectly supports the mechanism proposed for the formation of 5−7. The mechanisms of formation of 9−12 were verified by in situ reaction involving 7 and PPh 3 (1 and 2 equiv) through 19 F NMR spectroscopy. The new compounds were fully characterized, and molecular structures of 1, 3•C 7 H 8 , 4−6, 8•C 7 H 8 , 9, and 10•H 2 O were determined by SCXRD. The CNN tridentate guanidinate ligands were present in monoanionic (3•C 7 H 8 , 4 and 8•C 7 H 8 ), mono-and dianionic (5 and 6), and dianionic (9 and 10•H 2 O) forms, and hence the structures of 5 and 6 are unprecedented. Complex 3•C 7 H 8 was used as an efficient catalyst in Suzuki−Miyaura reactions involving sterically hindered aryl bromides and aryl boronic acids.

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Regioselective C–H/C–X activation of naphthyl-derived ligands to form six-membered palladacycles

Cited by 8 publications

References 36 publications

Pyridyl-Directed C–H and C–Br Bond Activations Promoted by Dimer Iridium-Olefin Complexes

Pyridyl-Directed C–H and C–Br Bond Activations Promoted by Dimer Iridium-Olefin Complexes

Guanidine-centred reactivity of CNN Pd(ii) pincer complexes including carboxylate-assisted N–H activation and –CH₂– → –C(O)– oxygenation

[6,5] CNN Palladium(II) Pincer Complexes Containing N-Substituted Monoanionic and Dianionic Guanidinate Ligands: Syntheses, Structural Aspects, and Their Utility in Suzuki–Miyaura Coupling Reactions

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Regioselective C–H/C–X activation of naphthyl-derived ligands to form six-membered palladacycles

Cited by 8 publications

References 36 publications

Pyridyl-Directed C–H and C–Br Bond Activations Promoted by Dimer Iridium-Olefin Complexes

Pyridyl-Directed C–H and C–Br Bond Activations Promoted by Dimer Iridium-Olefin Complexes

Guanidine-centred reactivity of CNN Pd(ii) pincer complexes including carboxylate-assisted N–H activation and –CH2– → –C(O)– oxygenation

[6,5] CNN Palladium(II) Pincer Complexes Containing N-Substituted Monoanionic and Dianionic Guanidinate Ligands: Syntheses, Structural Aspects, and Their Utility in Suzuki–Miyaura Coupling Reactions

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Guanidine-centred reactivity of CNN Pd(ii) pincer complexes including carboxylate-assisted N–H activation and –CH₂– → –C(O)– oxygenation