Reactions of Vinyl and Aryl Triflates with Hypervalent Tin Reagents

Martı́nez, Antonio Garcı́a; Barcina, José Osío; Heras, and María del Rosario Colorado; Cerezo, Álvaro de Fresno

doi:10.1021/om000957a

Cited by 35 publications

(11 citation statements)

References 27 publications

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“…Mixing of 6 with TBAF in benzene- d 6 at ambient temperature showed the formation of a distinctive septet at δ −194.3 ( 3 J F−H ∼ 6.0 Hz) for PhGeMe 2 F in agreement with the literature report for similar compounds . Prolonged time and/or heating promoted equilibration with perfluorinated species [δ −150.8 (br s), −126.4 (br s)] analogous to the reported hypervalent tin − and silicon − species, which were successfully utilized in cross-coupling reactions.…”

supporting

confidence: 86%

Arylchlorogermanes/TBAF/“Moist” Toluene: A Promising Combination for Pd-Catalyzed Germyl-Stille Cross-Coupling

et al. 2010

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The trichlorophenyl,-dichlorodiphenyl,-and chlorotriphenylgermanes undergo Pd-catalyzed crosscouplings with aryl bromides and iodides in the presence of TBAF in toluene with addition of the measured amount of water. One chloride ligand on the Ge center allows efficient activation by fluoride to promote transfer of one, two or three phenyl groups from the organogermane precursors.The Pd-catalyzed cross-coupling of organogermanes has thus far received much less attention 1 than the couplings involving organostannanes and organosilanes. 2 This is due to the lower reactivity of tetracoordinated organogermanium species, the less developed syntheses of vinyl/aryl germanyl derivatives, and the higher cost of germanium relative to silicon. 3 The carbagermatranes 1, with internal coordination of nitrogen to germanium, were the first examples of reactive tetracoordinated germanes applied to Pd-catalyzed cross-coupling reactions with aryl bromides 4 (Figure 1). The oxagermatranes 2 were found to be more efficient than carbagermatranes and triethoxygermanes. 5,6 Fluoride-promoted couplings with aryltri(2-furyl)germanes 7 and NaOH-activated couplings with arylgermanium trichlorides 8 or their hydrolyzed and stable sesquioxide alternatives 9 were also reported. The bis(2-naphthylmethyl) arylgermanes 3 were developed as photochemically activated arylgermanes for the synthesis of biaryls. 10,11 The vinyl tris(trimethylsilyl)germanes 4 were employed as transmetalation reagents in "ligand-and fluoride-free" coupling reactions with halides under oxidative wnuk@fiu.edu. † On faculty leave from

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supporting

confidence: 86%

Arylchlorogermanes/TBAF/“Moist” Toluene: A Promising Combination for Pd-Catalyzed Germyl-Stille Cross-Coupling

et al. 2010

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“…Shirakawa et al attributed enhancement of LiCl on the reactivity of PhZnI in the transition-metal-free coupling with aryl halides on the generation of nucleophilic lithium zincates complexes, such as Li + [PhZnICl] − . It is noteworthy that hypervalent fluoro tin , (e.g.,difluorotriphenylstannate), silicon, , and germane species have been established as active intermediates in Pd-catalyzed couplings.…”

mentioning

confidence: 99%

Transition-Metal-Free Cross-Coupling of Aryl Halides with Arylstannanes

Wang

Liang

et al. 2016

J. Org. Chem.

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Transition-metal-free LiCl-promoted cross-coupling reactions of tetraphenyltin, trichlorophenyl-, dichlorodiphenyl-, and chlorotriphenylstannanes with aryl halides in DMF provided access to biaryls in good to high yields. Up to four phenyl groups were transferred from the organostannanes substrates. The aryls bearing electron-withdrawing groups in either halides or organotin substrates gave coupling products in higher yields. The methodology has been applied for the efficient synthesis of ipriflavones.

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“…A high catalyst loading is maintained in the presence of Cl − and the catalytic reactions become faster 4. The accelerating effect of fluoride ions in Stille reactions5 is proposed to be due to the formation of anionic [R′SnFR 3 ] − , which is assumed to be more reactive in the transmetallation step with [ArPdXL n ] than the neutral R′SnR 3 5b,e,f. However, a triple role of fluoride ions in the Suzuki–Miyaura7 and Hiyama reactions8 was recently discovered.…”

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confidence: 99%

On the Triple Role of Fluoride Ions in Palladium‐Catalyzed Stille Reactions

Hervé

Lefèvre

Mitchell

et al. 2015

Chemistry A European J

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The mechanism of Stille reactions (cross-coupling of ArX with Ar'SnnBu3 ) performed in the presence of fluoride ions is established. A triple role for fluoride ions is identified from kinetic data on the rate of the reactions of trans-[ArPdBr(PPh3 )2 ] (Ar=Ph, p-(CN)C6 H4 ) with Ar'SnBu3 (Ar'=2-thiophenyl) in the presence of fluoride ions. Fluoride ions promote the rate-determining transmetallation by formation of trans-[ArPdF(PPh3 )2 ], which reacts with Ar'SnBu3 (Ar'=Ph, 2-thiophenyl) at room temperature, in contrast to trans-[ArPdBr(PPh3 )2 ], which is unreactive. However, the concentration ratio [F(-) ]/[Ar'SnBu3 ] must not be too high, because of the formation of unreactive anionic stannate [Ar'Sn(F)Bu3 ](-) . This rationalises the two kinetically antagonistic roles exerted by the fluoride ions that are observed experimentally, and is found to be in agreement with the kinetic law. In addition, fluoride ions promote reductive elimination from trans-[ArPdAr'(PPh3 )2 ] generated in the transmetallation step.

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Reactions of Vinyl and Aryl Triflates with Hypervalent Tin Reagents

Cited by 35 publications

References 27 publications

Arylchlorogermanes/TBAF/“Moist” Toluene: A Promising Combination for Pd-Catalyzed Germyl-Stille Cross-Coupling

Arylchlorogermanes/TBAF/“Moist” Toluene: A Promising Combination for Pd-Catalyzed Germyl-Stille Cross-Coupling

Transition-Metal-Free Cross-Coupling of Aryl Halides with Arylstannanes

On the Triple Role of Fluoride Ions in Palladium‐Catalyzed Stille Reactions

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