Mechanism of formation of Grignard reagents. Kinetics of reaction of alkyl halides in diethyl ether with magnesium

Reaction of 1-chloro-2,4,6-trinitrobenzene (I) with anions of 2,4-pentanedione (II) and methyl 3-oxobutanoate (III) produces 3-(2,4,6-trinitrophenyl)-2,4-pentanedione (IV) and methyl 2-(2,4,6-trinitrophenyl)-3-oxobutanoate (V), respectively, besides 2,4,6-trinitrophenol (VI). Amount of 2,4,6-trinitrophenol decreases with increasing amount of dimethyl sulphoxide and 2,4-pentanedione in methanol. A mechanism of formation of 2,4,6-trinitrophenol is suggested. Rate constant of formation of 3-(2,4,6-trinitrophenyl)-2,4-pentanedione in methanol-dimethyl sulphoxide mixtures increases with increasing content of dimethyl sulphoxide and decreases with increasing LiCl concentration. In methanol, 1-chloro-2,4,6-trinitrobenzene reacts with anion of 2,4-pentanedione about 20x slower than with anion of methyl 3-oxobutanoate.

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ChemInform Abstract: MECHANISM OF FORMATION OF GRIGNARD REAGENTS. CORROSION OF METALLIC MAGNESIUM BY ALKYL HALIDES IN ETHERS

Chemischer Informationsdienst ◽

10.1002/chin.198027248 ◽

1980 ◽

Vol 11 (27) ◽

Author(s):

C. L. HILL ◽

J. B. VANDER SANDE ◽

G. M. WHITESIDES

Keyword(s):

Alkyl Halides ◽

Grignard Reagents ◽

Mechanism Of Formation ◽

Metallic Magnesium

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Fe-Catalyzed Conjunctive Cross-Couplings of Unactivated Alkenes with Grignard Reagents

10.26434/chemrxiv.12049377.v1 ◽

2020 ◽

Author(s):

Lei Liu ◽

Wes Lee ◽

Cassandra R. Youshaw ◽

Mingbin Yuan ◽

Michael B. Geherty ◽

...

Keyword(s):

Functional Groups ◽

Cross Coupling ◽

Alkyl Halides ◽

Grignard Reagents ◽

Turnover Frequency ◽

Diverse Range ◽

Cascade Cyclization ◽

Radical Cascade

The first iron-catalyzed three-component cross-coupling of unactivated olefins with alkyl halides and Grignard reagents is reported. The reaction operates under fast turnover frequency and tolerates a diverse range of sp2-hybridized nucleophiles, alkyl halides, and unactivated olefins bearing diverse functional groups to yield the desired 1,2-alkylarylated products with high regiocontrol. Further, we demonstrate that this protocol is amenable for the synthesis of new (hetero)carbocycles including tetrahydrofurans and pyrrolidines via a three-component radical cascade cyclization/arylation that forges three new C-C bonds.

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Design and Development of Fe-Catalyzed Intra- and Intermolecular Carbofunctionalization of Vinyl Cyclopropanes

10.26434/chemrxiv.9858500.v1 ◽

2019 ◽

Cited By ~ 1

Author(s):

Lei Liu ◽

Wes Lee ◽

Mingbin Yuan ◽

Chris Acha ◽

Michael B. Geherty ◽

...

Keyword(s):

Bond Formation ◽

Cross Coupling ◽

Alkyl Halides ◽

Grignard Reagents ◽

Mechanistic Studies ◽

Radical Intermediates ◽

Design And Implementation ◽

Solvent Cage ◽

Radical Cascade ◽

Radical Processes

Design and implementation of the first (asymmetric) Fe-catalyzed intra- and intermolecular difunctionalization of vinyl cyclopropanes (VCPs) with alkyl halides and aryl Grignard reagents has been realized via a mechanistically driven approach. Mechanistic studies support the diffusion of the alkyl radical intermediates out of the solvent cage to participate in an intra- or -intermolecular radical cascade with the VCP followed by re-entering the Fe radical cross-coupling cycle to undergo selective C(sp2)-C(sp3) bond formation. Overall, we provide new design principles for Fe-mediated radical processes and underscore the potential of using combined computations and experiments to accelerate the development of challenging transformations.

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