Synthesis of Tetranuclear Palladium(II) Complexes and Their Catalytic Activity for Cross‐Coupling Reactions

Puls, Florian; Richter, Nils; Kataeva, О. N.; Knölker, Hans‐Joachim

doi:10.1002/chem.201703926

Cited by 8 publications

(1 citation statement)

References 114 publications

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“…Even higher TON than with iodoaryls have been obtained. For the reaction of 4-bromoacetophenone with phenylboronic acid, at RT and using tetranuclear palladium(II) complexes in NMP/water, a TON of 530,000 and a TOF of 23,000 h −1 were obtained (Table 1, entry 10) [33]. The same reaction was also performed during a very short experiment of 5 min with a temperature increase from RT to 150 • C using a micro-wave heating source [19].…”

Section: Recognized Homogeneous Catalystsmentioning

confidence: 99%

About Solid Phase vs. Liquid Phase in Suzuki-Miyaura Reaction

2019

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A critical review of conclusions about the putative heterogeneous mechanism in the Suzuki-Miyaura coupling by supported Pd solids is reported. In the first section, the turnover frequencies (TOF) of 20 well-established homogeneous catalysts are shown to be in the range 200 to 1,000,000,000 h − 1 . The evidences used to prove a heterogeneous mechanism are discussed and another interpretation is proposed, hypothesizing that only the leached species are responsible for the catalytic reaction, even at ppb levels. Considering more than 40 published catalytic systems for which liquid phase Pd content have been reported, activities have been computed based on leached Pd concentrations and are shown to be in the range TOF 150 to 70,000,000 h − 1 . Such values are compatible with those found for the well-established homogeneous catalysts which questions the validity of the conclusions raised by many papers about the heterogeneous (solid) nature of Suzuki-Miyaura catalysis. Last, a tentative methodology is proposed which involves the rational use of well-known tests (hot-filtration test, mercury test…) to help to discriminate between homogeneous and heterogeneous mechanisms.

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Section: Recognized Homogeneous Catalystsmentioning

confidence: 99%

About Solid Phase vs. Liquid Phase in Suzuki-Miyaura Reaction

2019

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Aromatic Substitution

Crampton¹

2020

Organic Reaction Mechanisms Series

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A Palladium NNC‐Pincer Complex as an Efficient Catalyst Precursor for the Mizoroki−Heck Reaction

2018

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The Mizoroki−Heck reaction of aryl halides (iodides, bromides, or chlorides) with activated alkenes in the presence of a palladium NNC‐pincer complex at ppb to ppm loadings gave the corresponding internal alkenes in excellent yields. The total turnover number and turnover frequency reached up to 8.70×108 and 1.21×107 h−1 (3.36×103 s−1), respectively. The catalyst was applied in a ten‐gram‐scale synthesis of the UV‐B sunscreen agent octinoxate (2‐ethylhexyl 4‐methoxycinnamate). Reaction‐rate analyses, transmission electron microscopic examination of the reaction mixture, and poisoning tests suggested that a monomeric palladium species is the catalytically active species in the catalytic cycle.magnified image

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Synthesis of Tetranuclear Palladium(II) Complexes and Their Catalytic Activity for Cross‐Coupling Reactions

Cited by 8 publications

References 114 publications

About Solid Phase vs. Liquid Phase in Suzuki-Miyaura Reaction

About Solid Phase vs. Liquid Phase in Suzuki-Miyaura Reaction

Aromatic Substitution

A Palladium NNC‐Pincer Complex as an Efficient Catalyst Precursor for the Mizoroki−Heck Reaction

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