Synthesis of Polyarylated Methanes through Cross‐Coupling of Tricarbonylchromium‐Activated Benzyllithiums

McGrew, Genette I.; Temaismithi, Jesada; Carroll, Patrick J.; Walsh, Patrick J.

doi:10.1002/ange.201000957

Cited by 42 publications

(6 citation statements)

References 31 publications

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“…Mechanistically, initial deprotonation of [(η 6 ‐benzylamine)Cr(CO) 3 ] by LiN(SiMe 3 ) 2 was anticipated to be rapid based on the chemistry in Scheme 3a. Because of the ability of {Cr(CO) 3 } to delocalize negative charge,6 the lithiated intermediates 1 ‐Li and 1 ‐Li′ (Scheme ) were expected to be planar chiral and configurationally stable owing to the partial double bond character between the ipso and benzylic carbon atoms 7.…”

Section: Methodsmentioning

confidence: 99%

Asymmetric Cross‐Coupling of Aryl Triflates to the Benzylic Position of Benzylamines

et al. 2012

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Ligand im Heuhaufen: Bei der Titelreaktion von lithiierten Benzylsubstraten mit tertiären Aminfunktionen in α‐Stellung wird die benzylische C sp 3‐H‐Bindung durch {Cr(CO)3}‐Komplexierung aktiviert. Die anschließende Pd‐katalysierte Kupplung mit Aryltriflaten (ArOTf) ergibt über eine neuartige dynamische kinetische Racematspaltung die enantiomerenangereicherten Diarylmethylamine. Der chirale Ligand wurde in Hochdurchsatzexperimenten unter 192 Liganden identifiziert.

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Section: Methodsmentioning

confidence: 99%

Asymmetric Cross‐Coupling of Aryl Triflates to the Benzylic Position of Benzylamines

et al. 2012

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“…In 2010, Patrick J. Walsh and co-workers reported a palladium-catalyzed cross-coupling of tricarbonylchromium-activated benzyllithiums for the synthesis of polyarylated methanes (Scheme 32). [49] The reported method complements the Friedel-Craft approach and involves the activation of the benzylic protons of [(η 6 -arene)Cr(CO) 3 ] and in situ generation of benzyllithium with the aid of LiN(SiMe 3 ). Subsequently, it directly participates in the palladium-catalyzed cross-coupling to generate polyarylated products including unsymmetrically substituted triarylmethanes.…”

Section: Palladium-catalyzed Functionalizationmentioning

confidence: 99%

Benzylic Methylene Functionalizations of Diarylmethanes

Gulati

Gandhi

Laha

2020

Chemistry An Asian Journal

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Diarylmethanes are cardinal scaffolds by virtue of their unique structural feature including the presence of a benzylic CH 2 group that can be easily functionalized to generate a variety of fascinating molecules holding immense importance in pharmaceutical, agrochemical, and material sciences. While the originally developed protocols for benzylic CÀ H functionalization in diarylmethanes employing base-mediated and metal-catalyzed strategies are still actively used, they are joined by a new array of metal-free conditions, offering milder and benign conditions. With the recent surge of interest towards the synthesis of functionalized diarylmethanes, numerous choices are now available for a synthetic organic chemist to transform the benzylic CÀ H bond to CÀ C or CÀ X bond offering the synthesis of any molecule of choice. This review highlights benzylic methylene (CH 2) functionalizations of diaryl/heteroarylmethanes utilizing various base-mediated, transition-metal-catalyzed, and transition-metal free approaches for the synthesis of structurally diverse important organic molecules, often with a high chemo-, regio-and enantio-selectivity. This review also attempts to provide analysis of the scope and limitations, mechanistic understanding, and sustainability of the transformations.

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“…For unactivated toluene derivatives, however, we conjectured that the high p K a values (≈43 in DMSO 18 ) of the benzylic C–Hs were far beyond the reach of MN(SiMe 3 ) 2 bases [M = alkali metal, p K a ≈ 26 for HN(SiMe 3 ) 2 in THF 19 ]. Thus, to address this long-standing challenge, we 20 , 21 and others 22 activated the arenes with stoichiometric transition metals by forming ( η 6 -toluene)Cr(CO) 3 complexes. The benzylic C–Hs of ( η 6 -toluene)Cr(CO) 3 exhibit increased acidity and are reversibly deprotonated with LiN(SiMe 3 ) 2 , enabling functionalization (Fig.…”

Section: Introductionmentioning

confidence: 99%

One-pot aminobenzylation of aldehydes with toluenes

Wang

Zheng

et al. 2018

Nat Commun

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Amines are fundamental motifs in bioactive natural products and pharmaceuticals. Using simple toluene derivatives, a one-pot aminobenzylation of aldehydes is introduced that provides rapid access to amines. Simply combining benzaldehydes, toluenes, NaN(SiMe3)2, and additive Cs(O2CCF3) (0.35 equiv.) generates a diverse array of 1,2-diarylethylamine derivatives (36 examples, 56–98% yield). Furthermore, suitably functionalized 1,2-diarylethylamines were transformed into 2-aryl-substituted indoline derivatives via Buchwald–Hartwig amination. It is proposed that the successful deprotonation of toluene by MN(SiMe3)2 is facilitated by cation–π interactions between the arene and the group(I) cation that acidify the benzylic C–Hs.

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Synthesis of Polyarylated Methanes through Cross‐Coupling of Tricarbonylchromium‐Activated Benzyllithiums

Cited by 42 publications

References 31 publications

Asymmetric Cross‐Coupling of Aryl Triflates to the Benzylic Position of Benzylamines

Asymmetric Cross‐Coupling of Aryl Triflates to the Benzylic Position of Benzylamines

Benzylic Methylene Functionalizations of Diarylmethanes

One-pot aminobenzylation of aldehydes with toluenes

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