Rearrangement of Metallabenzynes to Chlorocyclopentadienyl Complexes

Chen, Jiangxi; Lee, Ka‐Ho; Wen, Ting Bin; Gao, Feng; Sung, Herman H. Y.; Williams, Ian D.; Lin, Zhenyang; Jia, Guochen

doi:10.1021/om501181u

Cited by 36 publications

(34 citation statements)

References 83 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This Rh(OAc) 2 Cp*-catalyzed reaction was studied by Chen and Lin who reported M06(DCE) energetics with an additional D3 correction [81]. After deprotonation, the terminal NAc position acts as a directing group for a two- give indoles [81]. Double arrows indicate several steps are involved, with the energy of the highest transition state between the two minima indicated in square brackets.…”

Section: Heterocycle Formation With Internal Oxidantsmentioning

confidence: 99%

Computational Studies of Heteroatom‐Assisted CH Activation at Ru, Rh, Ir, and Pd as a Basis for Heterocycle Synthesis and Derivatization

Carr¹,

Macgregor²,

McMullin³

2016

Transition Metal‐Catalyzed Heterocycle Synthesis via CH Activation

View full text Add to dashboard Cite

IntroductionModern computational chemistry is a key tool by which insight into organometallic reaction mechanisms can be gained. The ability to characterize short-lived intermediates and transition states provides an ideal complement to experiment, where such information is often extremely difficult, if not impossible, to obtain. Recent years have seen great advances in understanding the mechanisms of C-H bond activation, and this area was the subject of several major reviews toward the end of the last decade [1,2]. More recently, the focus has shifted to how C-H activation can be integrated into catalytic cycles for useful organic transformations. The C-H bond activation event is itself mechanistically diverse, with oxidative addition (OA), σ-bond metathesis (SBM), and electrophilic activation (EA) all potentially available at late transition metal centers, depending on the metal, its oxidation state, and the coordination environment. C-H activation assisted by a heteroatom base (typically a carboxylate or carbonate) falls into the last of these categories and forms the focus of this chapter. More recently, computational studies of catalytic cycles for C-H activation and functionalization have become more common. These reveal the complexity of what are usually multiple-step processes, and calculations are particularly well placed to test different mechanistic possibilities. Such studies are most effectively pursued through a close interaction between experiment and computation, and increasingly this is allowing for a more quantitative assessment of computed reaction mechanisms.As well as progress in mechanistic understanding, the last 10 years have seen important developments in the computational methodologies available to model transition metal reactivity. While density functional theory (DFT) remains the core method of choice, the ability to model larger systems that more closely reflect experiment has highlighted the known shortcomings of DFT in describing dispersion interactions. These long-range, stabilizing interactions are individually weak, but their cumulative effect in large systems can be significant. Methods to incorporate this component include its separate calculation (e.g., Transition Metal-Catalyzed Heterocycle Synthesis via C-H Activation, First Edition. Edited by Xiao-Feng Wu.

show abstract

Section: Heterocycle Formation With Internal Oxidantsmentioning

confidence: 99%

Computational Studies of Heteroatom‐Assisted CH Activation at Ru, Rh, Ir, and Pd as a Basis for Heterocycle Synthesis and Derivatization

Carr¹,

Macgregor²,

McMullin³

2016

Transition Metal‐Catalyzed Heterocycle Synthesis via CH Activation

View full text Add to dashboard Cite

show abstract

“…Compared with the chemistry of annulenes and dehydroannulenes, that of metalla-analogs is much less developed. Reported metallaannulenes or metalladehydroannulenes are mainly small-ring metallacycles, such as metallacyclobutadienes (1), [2,3] metallabenzenes (2), [4] dimetallabenzenes (3), [6] metallabenzynes (4), [7,8] metallacyclooctatetrenes [9a] and ten-membered-ring dimetallaannulenes (5), [9b-d] despite the fact that many polycyclic metalla-aromatics (6)(7)(8)(9)(10)(11) [10] or spiro-aromatic metallacycles (12) [11] have been reported.…”

Section: Introductionmentioning

confidence: 99%

Synthesis, Characterization and Electronic Structure of Dirhenadehyro[12]annulene Complexes

et al. 2018

Self Cite

View full text Add to dashboard Cite

Treatment of the SiMe3‐protected dichloro‐rhenium carbyne complexes Re{≡CCH=C(R)C≡CSiMe3}Cl2(PMe2Ph)3 (R = CMe3, 1‐adamantyl) with CsF in methanol directly afforded the 12‐membered metallacycles {ReCl(PMe2Ph)3}2{≡CCH=C(R)C≡C−}2. The electronic structure of the metallacycle was investigated by density functional calculations. The UV‐vis spectrum of the metallacycle shows a red‐shifted band compared to that of the starting dichlorocarbyne complex. Treatment of {ReCl(PMe2Ph)3}2{≡CCH=C(CMe3)C≡C−}2 with HCl produced the dichloro‐rhenium carbyne complex Re{≡CCH=C(CMe3)C≡CH}Cl2(PMe2Ph)3, which is consistent with the electronic structure of the 12‐membered metallacycles.

show abstract

“…21 Making clear if Rh(V) species are also involved in the current systems will be useful for understanding the mechanism of C−N formation in related reactions. 22 Answering the above mechanistic problems with the furanyland phenyl-involved C−H activations should have implications for the design of novel transformations. Hence, in the current report a comprehensive DFT study was carried out to investigate the mechanisms of the Rh(III)-catalyzed C−H activation/cycloaddition of benzamides and MCPs.…”

Section: ■ Introductionmentioning

confidence: 99%

Mechanistic Understanding of the Aryl-Dependent Ring Formations in Rh(III)-Catalyzed C–H Activation/Cycloaddition of Benzamides and Methylenecyclopropanes by DFT Calculations

2015

View full text Add to dashboard Cite

The divergence between Rh(III)-catalyzed C− H activation/cycloaddition of phenyl-and 2-furanyl-containing benzamides with methylenecyclopropanes (MCP) was studied by DFT calculations. Calculations found that the C−H activation via a CMD mechanism is the most difficult step of the reaction involving phenyl. In contrast, the C−H activation of the 2-furanyl-containing substrate is kinetically easier but the formed five-membered rhodacycle is relatively unstable, making the following MCP insertion more difficult. Thus, different KIE data was obtained in experiments. The MCP insertion forms a seven-membered-ring rhodacycle intermediate, from which the chemoselectivity of the whole reaction is determined by the competitive pivalate migration (path I) and β-C elimination (path II). While the β-C elimination is lower in energy when a furanylene is contained in the intermediate, a reversed preference of pivalate migration was predicted for the phenylene counterpart. Structural analysis suggested that the unfavorable β-C elimination in the phenylene case should be attributed to the obviously increased ring strain in the corresponding transition state, instead of the difference in electronic properties between the aryl groups. This accounts for why aryl-dependent chemoselectivity was observed. In addition, the results indicated that for both paths I and II the generation of a Rh(V)−nitrenoid intermediate from pivalate migration is crucial for the final C−N bond formation. This explains why no reaction occurred when the N−OPiv moiety was replaced with an N−OMe group, as no Rh(V) intermediate could be formed in this system.

show abstract

Rearrangement of Metallabenzynes to Chlorocyclopentadienyl Complexes

Cited by 36 publications

References 83 publications

Computational Studies of Heteroatom‐Assisted CH Activation at Ru, Rh, Ir, and Pd as a Basis for Heterocycle Synthesis and Derivatization

Computational Studies of Heteroatom‐Assisted CH Activation at Ru, Rh, Ir, and Pd as a Basis for Heterocycle Synthesis and Derivatization

Synthesis, Characterization and Electronic Structure of Dirhenadehyro[12]annulene Complexes

Mechanistic Understanding of the Aryl-Dependent Ring Formations in Rh(III)-Catalyzed C–H Activation/Cycloaddition of Benzamides and Methylenecyclopropanes by DFT Calculations

Contact Info

Product

Resources

About