Efficient Synthesis of Functionalized Organozinc Compounds by the Direct Insertion of Zinc into Organic Iodides and Bromides.

Krasovskiy, Arkady; Malakhov, Vladimir; Gavryushin, Andrei; Knöchel, Paul

doi:10.1002/chin.200652185

Cited by 22 publications

(38 citation statements)

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“…Upon completed addition, the reaction mixture was heated to 50 8Ca nd allowed to reflux for 1h.T he soformed Grignard solutions were titrated before being used in the Hammett studies. [24] General procedure for competitive Hammett study with cyclohexyl bromide Ap redried, 100 mL round-bottomed flask was equipped with am agnetic stir bar,F eBr 3 (15 mg, 0.05 mmol, 5mol %), and then sealed with ar ubber septum. The flask was evacuated and refilled with N 2 four times and then charged with dry Et 2 O( 60 mL), dodecane (225 mL, 1mmol), and Ar(A)MgBr (600 mL, 1.2 mmol, 2 m in Et 2 O) followed by stirring for 5min.…”

Section: General Procedures For the Preparation Of Grignard Solutionsmentioning

confidence: 99%

On the Radical Nature of Iron‐Catalyzed Cross‐Coupling Reactions

Hedström

Izakian

Vreto

et al. 2015

Chemistry A European J

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The radical nature of iron-catalyzed cross-coupling between Grignard reagents and alkyl halides has been studied by using a combination of competitive kinetic experiments and DFT calculations. In contrast to the corresponding coupling with aryl halides, which commences through a classical two-electron oxidative addition/reductive elimination sequence, the presented data suggest that alkyl halides react through an atom-transfer-initiated radical pathway. Furthermore, a general iodine-based quenching methodology was developed to enable the determination of highly accurate concentrations of Grignard reagents, a capability that facilitates and increases the information output of kinetic investigations based on these substrates.

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Section: General Procedures For the Preparation Of Grignard Solutionsmentioning

confidence: 99%

On the Radical Nature of Iron‐Catalyzed Cross‐Coupling Reactions

Hedström

Izakian

Vreto

et al. 2015

Chemistry A European J

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“…It should be emphasized that the coupling reaction with acid chlorides was carried out in the absence of any transition metal catalyst under mild conditions. Generally, a copper catalyst is widely used for the coupling reactions of organozinc reagents [ 61 ]. Halobenzoyl chlorides were easily coupled with 2-pyridylzinc bromide ( P1 ) at rt to give the corresponding ketones ( 1a , 1b , 1c , 1d and 1e , Table 1 ) in moderate yields.…”

Section: Resultsmentioning

confidence: 99%

Recent Advance in Heterocyclic Organozinc and Organomanganese Compounds; Direct Synthetic Routes and Application in Organic Synthesis

Kim

Rieke

2010

Molecules

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A practical synthetic route for the preparation of 2-pyridyl and 3-pyridyl derivatives has been accomplished by utilizing a simple coupling reaction of stable 2-pyridylzinc bromides and 3-pyridylzinc bromides. The organozincs used in this study were easily prepared via the direct insertion of active zinc into the corresponding bromopyridines. The subsequent coupling reactions with a variety of different electrophiles have afforded the corresponding coupling products. Using highly active manganese, a variety of Grignard-type organomanganese reagents have been obtained. The subsequent coupling reactions of the resulting organomanganese reagents with several electrophiles have also been accomplished under mild conditions.

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“…The concentrations of the organometallic reagents were determined by iodometric titration. [51] (E)-Buta-1,3dien-1-yltriphenylphosphonium bromide and (6-bromohexyl)triphenylphosphonium bromide were synthesized in analogy to procedures reported in the literature. [52][53][54] Sample solutions were prepared by dissolving [Pd 2 (dba) 3 ]i nd ry THF and addition of the diene followed by stirring at room temperature for 45 min.…”

Section: Experimental Section Generalmentioning

confidence: 99%

Formation of Transient Anionic Metal Clusters in Palladium/Diene‐Catalyzed Cross‐Coupling Reactions

Kolter

Koszinowski

2019

Chemistry A European J

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Despite their considerable practical value, palladium/1,3‐diene‐catalyzed cross‐coupling reactions between Grignard reagents RMgCl and alkyl halides AlkylX remain mechanistically poorly understood. Herein, we probe the intermediates formed in these reactions by a combination of electrospray‐ionization mass spectrometry, UV/Vis spectroscopy, and NMR spectroscopy. According to our results and in line with previous hypotheses, the first step of the catalytic cycle brings about transmetalation to afford organopalladate anions. These organopalladate anions apparently undergo SN2‐type reactions with the AlkylX coupling partner. The resulting neutral complexes then release the cross‐coupling products by reductive elimination. In gas‐phase fragmentation experiments, the occurrence of reductive eliminations was observed for anionic analogues of the neutral complexes. Although the actual catalytic cycle is supposed to involve chiefly mononuclear palladium species, anionic palladium nanoclusters [PdnR(DE)n]−, (n=2, 4, 6; DE=diene) were also observed. At short reaction times, the dinuclear complexes usually predominated, whereas at longer times the tetra‐ and hexanuclear clusters became relatively more abundant. In parallel, the formation of palladium black pointed to continued aggregation processes. Thus, the present study directly shows dynamic behavior of the palladium/diene catalyst system and degradation of the active catalyst with increasing reaction time.

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Efficient Synthesis of Functionalized Organozinc Compounds by the Direct Insertion of Zinc into Organic Iodides and Bromides.

Cited by 22 publications

References 1 publication

On the Radical Nature of Iron‐Catalyzed Cross‐Coupling Reactions

On the Radical Nature of Iron‐Catalyzed Cross‐Coupling Reactions

Recent Advance in Heterocyclic Organozinc and Organomanganese Compounds; Direct Synthetic Routes and Application in Organic Synthesis

Formation of Transient Anionic Metal Clusters in Palladium/Diene‐Catalyzed Cross‐Coupling Reactions

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