Investigating the Dearomative Rearrangement of Biaryl Phosphine-Ligated Pd(II) Complexes

Milner, Phillip J.; Maimone, Thomas J.; Su, Mingjuan; Chen, Jiahao; Müller, Péter; Buchwald, Stephen L.

doi:10.1021/ja310351e

Cited by 88 publications

(80 citation statements)

References 93 publications

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“…A nearly identical species bearing a related ligand and also possessing η 3 -binding of the dearomatized ring to the Pd center has been previously reported [14]. This species likely does not form by oxidative addition of 1 •Pd(0) to CDCl 3 followed by a dearomative rearrangement similar to that reported for other Pd(II) complexes of 1 [7,9] because the CDCl 2 and Pd center are bound to opposite faces of the lower ring of the ligand. Instead, a carbene mechanism is proposed to be involved in the formation of 3 [14].…”

Section: Resultssupporting

confidence: 66%

“…CD 2 Cl 2 , CDCl 3 , and toluene-d 8 were purchased from Cambridge Isotopes in sealed ampules and used without further purification. Preparations of AdBrettPhos ( 1 ) [7], t BuBrettPhos ( 6 ) [8], RockPhos ( 7 ) [8], 2 [1], 5 [9], 12 [10], 13 [9], 14 [10], and 17 [11] have been previously described. The t BuXPhos ( 8 ) used in this work was purchased from Sigma Aldrich.…”

Section: Methodsmentioning

confidence: 99%

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Structure and reactivity of [(L·Pd) n ·(1,5-cyclooctadiene)] ( n = 1–2) complexes bearing biaryl phosphine ligands

Lee

Milner

Colvin

et al. 2014

Inorganica Chimica Acta

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The structure of the stable Pd(0) precatalyst [(1,5-cyclooctadiene)(L•Pd)2] (L = AdBrettPhos) for the Pd-catalyzed fluorination of aryl triflates has been further studied by solid state NMR and X-ray cystrallography of the analogous N-phenylmaleimide complex. The reactivity of this complex with CDCl3 to form a dearomatized complex is also presented. In addition, studies suggest that related bulky biaryl phosphine ligands form similar complexes, although the smaller ligand BrettPhos forms a monomeric [(1,5-cyclooctadiene)(L•Pd)] species instead.

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Section: Resultssupporting

confidence: 66%

Section: Methodsmentioning

confidence: 99%

Structure and reactivity of [(L·Pd) n ·(1,5-cyclooctadiene)] ( n = 1–2) complexes bearing biaryl phosphine ligands

Lee

Milner

Colvin

et al. 2014

Inorganica Chimica Acta

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“…These ligands form well-defined bidentate mono-P-liganded Pd(0) species [45][46][47][48] with the structures formally corresponding to the 12-electron Pd-P(III) active catalysts of the SM reaction (Scheme 2, AC). The active catalyst is extremely reactive and readily undergoes oxidative addition reaction with aromatic halides to form intermediates with a welldefined structure I [49,50].…”

Section: Methodsmentioning

confidence: 99%

A Quantum-Chemical DFT Approach to Elucidation of the Chirality Transfer Mechanism of the Enantioselective Suzuki–Miyaura Cross-Coupling Reaction

Jasiński

Demchuk

Babyuk

2017

Journal of Chemistry

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The DFT calculations of the simplified model of the asymmetric Suzuki-Miyaura coupling reaction were performed at the M062x/LANL2DZ theory level at first. It was found that enantioselective reactions mediated by the palladium complexes of chiral C,P-ligands follow a four-stage mechanism similar to that proposed previously as one of the most credible mechanisms. It should be underlined that the presence of substituents in the substrates and the chiral ligand at ortho positions determines the energies of possible diastereoisomeric transition states and intermediates in initial reaction steps. This suggests that, in practice, a sharp selection of theoretically possible paths of chirality transfer from the catalyst to the product should have a place and, therefore, the absolute configuration of the formed atropisomeric product is defined and can be predicted.

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“…[17] Thus,t he auxiliary ligands largely affect the s-p state of indole complexes.Itshould be noted that the positive charge of the indole ligand in the p( Thus,o ur experimental and theoretical results showed that there is the s-p continuum in indole-Pd II complexes.The s-p continuum has been previously observed in the h 1 -arenemetal complexes, [18,19] although the pure s-complexes of arenes (Wheland-intermediate-type) have been rarely identified due to the insufficient charge transfer between the arene ligand and am etal center.…”

mentioning

confidence: 94%

σ–π Continuum in Indole–Palladium(II) Complexes

2016

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The intrinsic features of (hetero-arene)-metal interactions have been elusive mainly because the systematic structure analysis of non-anchored hetero-arene-metal complexes has been hampered by their labile nature.W er eport successful isolation and systematic structure analysis of aseries of non-anchored indole-palladium(II) complexes.I tw as revealed that there is a s-p continuum for the indole-metal interaction, while it has been thought that the dominant coordination mode of indole to am etal center is the Wheland-intermediate-type s-mode in light of the seemingly strong electron-donating ability of indole.Several factors which affect the s-o rp-character of indole-metal interactions are discussed.The coordination behavior of hetero-arenes to at ransition metal center has attracted considerable attention since their coordination through low-hapticity modes have been thought to be involved in metal-mediated or metal-catalyzed transformations of hetero-arenes. [1,2] However,ithas been difficult to address the intrinsic features of (hetero-arene)-metal interactions,m ainly owing to the labile nature of nonanchored hetero-arene-metal complexes.I nf act, it is quite rare for non-anchored hetero-arene transition metal complexes to be isolated, and their structures has not been characterized by X-ray crystallography.[3] Nevertheless,ithas been assumed that Wheland-intermediate-type s-complexes are preferentially formed upon coordination of hetero-arenes to am etal center, in view of the seemingly greater electrondonating ability of hetero-arenes.F urthermore,s ynthetically useful palladium-catalyzed direct transformations of indoles have been proposed to be initiated by the formation of a sindole-palladium(II) complex, in which ametal center is s(h 1 -C)-bonded to the nucleophilic C3 atom of the indole ring, giving an indolium-type structure (A;Scheme 1).[1] However, the dominance of s-mode has not been verified by systematic structure analysis of non-anchored indole-metal complexes. We considered the possibility that the pure s-complexes are not always formed in (hetero-arene)-metal complexes;t hat is,f or the indole complexes, s/p-intermediate-(B)a nd pmodes (C or D)( Scheme 1) [4] may be taken into consideration, when the electron-donating property of ahetero-arene, or the electron-accepting property of am etal center is insufficient to induce strong intramolecular charge transfer. Herein, we confirmed the existence of a s-p continuum in (hetero-arene)-metal complexes through isolation and systematic structure analysis of non-anchored indole-metal complexes.To examine the (hetero-arene)-metal interaction, we chose non-anchored indole-Pd II complexes as model compounds because of their relevance to catalysis.I no ur study, the anchored indole complexes,ofwhich the isolation is much easier than that of non-anchored ones, [5] were not used because the chelating structures give rise to geometric constraints,w hich could affect the coordination modes of indole.[

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Investigating the Dearomative Rearrangement of Biaryl Phosphine-Ligated Pd(II) Complexes

Cited by 88 publications

References 93 publications

Structure and reactivity of [(L·Pd) n ·(1,5-cyclooctadiene)] ( n = 1–2) complexes bearing biaryl phosphine ligands

Structure and reactivity of [(L·Pd) n ·(1,5-cyclooctadiene)] ( n = 1–2) complexes bearing biaryl phosphine ligands

A Quantum-Chemical DFT Approach to Elucidation of the Chirality Transfer Mechanism of the Enantioselective Suzuki–Miyaura Cross-Coupling Reaction

σ–π Continuum in Indole–Palladium(II) Complexes

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