Palladium‐Catalyzed C–H Bond Acylation of Acetanilides with Benzylic Alcohols under Aqueous Conditions

Luo, Feihua; Yang, Jun; Li, Zhengkai; Xiang, Haifeng; Zhou, Xiangge

doi:10.1002/ejoc.201500016

Cited by 37 publications

(19 citation statements)

References 83 publications

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“…Good yields of the desired ketones were produced under the optimized conditions (Scheme ). This transformation was later studied further by Zhou and co‐workers 33b. By using TFA as an additive, the reaction could be performed under lower temperature in aqueous solution.…”

Section: Discussionmentioning

confidence: 99%

Acylation of (Hetero)Arenes through CH Activation with Aroyl Surrogates

2015

Chemistry A European J

133

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In this Minireview, the major achievements in the acylation of arenes and heteroarenes by C-H activation with aroyl groups are summarized and discussed. As the products are carbonyl-containing compounds that are typical products from carbonylation chemistry, the possible inspirations for these reactions are also discussed, as are mechanistic issues and possible problems for carbonylative diaryl ketone synthesis by C-H activation.

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Section: Discussionmentioning

confidence: 99%

Acylation of (Hetero)Arenes through CH Activation with Aroyl Surrogates

2015

Chemistry A European J

133

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“…In the end of the experiment, the spectra closely resemble the spectrum of a solution prepared by dissolution of independently prepared binuclear palladium complexes bearing deprotonated acetanilides as ligands. 30 The absorbance changes at 520 nm were fitted by the first order kinetic model to obtain the observed rate constants k obs (see Table 1 and Tables S5-S6 in Supporting Information).…”

Section: Reaction Kinetics By Uv-vis Experimentsmentioning

confidence: 99%

Palladium-Catalyzed C–H Activation: Mass Spectrometric Approach to Reaction Kinetics in Solution

et al. 2017

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We report a new method for determination of rate constants of processes in solution using electrospray ionization mass spectrometry (ESI-MS). The investigated reaction is C-H activation of acetanilides by palladium(II)trifluoroacetate leading to stable organopalladium complexes. The rate constants can be determined from an experiment with a couple of differently substituted acetanilides being in competition activated by the palladium salt. The formed organopalladium complexes can be detected by ESI-MS. The time dependence is achieved by adding one of the acetanilides to the reaction mixture with a time delay. The kinetics can be then evaluated from the evolution of the ratio of the ESI-MS signals of differently substituted complexes as a function of the time delay. The Hammett analysis of the rate constants obtained for a series of meta-and para-substituted acetanilides provides the ρ value of-1.5, which is in agreement with values reported for similar C-H activations. We have investigated the very same reaction also with UV-Vis spectroscopy that gave us about three times smaller rate constants, but the same trend with the ρ value of-1.6. The rate constants determined by ESI-MS are directly linked to the occurrence of organopalladium complexes, whereas the UV-Vis data are associated with an absorption spectra change that could involve more reaction steps. DFT calculations support the interpretation of the reaction mechanism as cyclopalladation and provide the ρ value in the same range. The rate determining step corresponds to the agostic C-H transition structure.

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“…1 A related alkylation reaction was made catalytic by adding AgOAc. 5 Many extensions to other TM-catalysed couplings, particularly with rhodium, have been conducted (Scheme 1). Electron-releasing substituents in the aromatic ring enhanced reactivity, and ratedetermining C-H activation was indicated by a primary KIE of 3 using ring-deuterated acetanilide.…”

Section: Introductionmentioning

confidence: 99%

Palladium-catalysed directed C–H activation by anilides and ureas; water participation in a general base mechanism

Rauf

Brown

2016

Org. Biomol. Chem.

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C-H activation plays a central role in organometallic catalysis. Concerted metallation-deprotonation (CMD) has been dominant as the pathway for C-H bond cleavage. In the course of studying the mechanism of C-H activation of arylamides and arylureas with Pd complexes as part of catalytic oxidative Heck reactions, DFT calculations were carried out. The turnover-limiting C-H activation is acid-catalysed and can occur readily in the absence of acetate or other coordinating bases. The calculations simulated experiment, so that ligated sulfonate and water, both previously observed by X-ray characterization, were incorporated in the model. A Wheland-type complex between acetanilide and Pd was readily located, but the reactive C-H and the coordinated sulfonate were poorly placed for intramolecular proton transfer. Involvement of a water molecule coordinated to sulfonate provides a low-energy pathway to the palladacycle. The relative reactivity of substituted acetanilides and arylureas according to this model fits well with existing literature. General-base catalysis as described here has broader potential.

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Palladium‐Catalyzed C–H Bond Acylation of Acetanilides with Benzylic Alcohols under Aqueous Conditions

Cited by 37 publications

References 83 publications

Acylation of (Hetero)Arenes through CH Activation with Aroyl Surrogates

Acylation of (Hetero)Arenes through CH Activation with Aroyl Surrogates

Palladium-Catalyzed C–H Activation: Mass Spectrometric Approach to Reaction Kinetics in Solution

Palladium-catalysed directed C–H activation by anilides and ureas; water participation in a general base mechanism

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