Novel Group-Transfer Three-Component Coupling of Silyltellurides, Carbonyl Compounds, and Isocyanides

Miyazoe, Hiroshi; Yamago, Shigeru; Yoshida, Jun‐ichi

doi:10.1002/1521-3773(20001016)39:20<3669::aid-anie3669>3.0.co;2-4

Cited by 45 publications

(13 citation statements)

References 37 publications

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“…In contrast, TEMPO had a negligible impact on reactions employing TES ( 1b ) and TIPS ( 1c ), even when present at much higher concentrations (80 mM TEMPO); the origins of this profound difference in behavior is discussed later. Nonetheless, further tests for discrete radical intermediates , were conclusively negative: 4-F-benzophenone ( 12 ) exclusively underwent 1,2-addition (Scheme , B), , cyclopropyl ketones ( 6/7 ) reacted without any trace of competing ring-opening (Scheme , C), and competition between ketone 2 and 4-biphenyl methyl ketone for limiting TMSCF 3 ( 1a ) favored 2 ( k rel = 1.93) …”

Section: Resultsmentioning

confidence: 99%

Anion-Initiated Trifluoromethylation by TMSCF₃: Deconvolution of the Siliconate–Carbanion Dichotomy by Stopped-Flow NMR/IR

et al. 2018

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The mechanism of CF3 transfer from R3SiCF3 (R = Me, Et, iPr) to ketones and aldehydes, initiated by M+X– (<0.004 to 10 mol %), has been investigated by analysis of kinetics (variable-ratio stopped-flow NMR and IR), 13C/2H KIEs, LFER, addition of ligands (18-c-6, crypt-222), and density functional theory calculations. The kinetics, reaction orders, and selectivity vary substantially with reagent (R3SiCF3) and initiator (M+X–). Traces of exogenous inhibitors present in the R3SiCF3 reagents, which vary substantially in proportion and identity between batches and suppliers, also affect the kinetics. Some reactions are complete in milliseconds, others take hours, and others stall before completion. Despite these differences, a general mechanism has been elucidated in which the product alkoxide and CF3– anion act as chain carriers in an anionic chain reaction. Silyl enol ether generation competes with 1,2-addition and involves protonation of CF3– by the α-C–H of the ketone and the OH of the enol. The overarching mechanism for trifluoromethylation by R3SiCF3, in which pentacoordinate siliconate intermediates are unable to directly transfer CF3– as a nucleophile or base, rationalizes why the turnover rate (per M+X– initiator) depends on the initial concentration (but not identity) of X–, the identity (but not concentration) of M+, the identity of the R3SiCF3 reagent, and the carbonyl/R3SiCF3 ratio. It also rationalizes which R3SiCF3 reagent effects the most rapid trifluoromethylation, for a specific M+X– initiator.

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Section: Resultsmentioning

confidence: 99%

Anion-Initiated Trifluoromethylation by TMSCF₃: Deconvolution of the Siliconate–Carbanion Dichotomy by Stopped-Flow NMR/IR

et al. 2018

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“…The first step is probably the spontaneous silyltelluration of benzophenone to give 1-siloxy-1-phenylbenzyl phenyl telluride. The second step is radical addition of the resulting telluride to phenyl isonitrile [14]. Subsequent electrolysis of the product gives the corresponding amide in high yield.…”

Section: Hetero-multicomponent Coupling Reactionsmentioning

confidence: 99%

Free‐Radical‐Mediated Multicomponent Coupling Reactions

Tojino

Ryu

2005

Multicomponent Reactions

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“…We recently found that organotellurium compounds undergo reversible carbon-tellurium bond cleavage upon thermolysis and photolysis, 23,24 and the resulting carbon-centered radicals can react with a variety of radical acceptors. 17,[25][26][27][28][29] During the course of investigating new radical-coupling reactions, we discovered that several organotellurium compounds serve as excellent mediators for living radical polymerization.…”

Section: Introductionmentioning

confidence: 99%

Development of organotellurium‐mediated and organostibine‐mediated living radical polymerization reactions

Yamago

2005

J. Polym. Sci. A Polym. Chem.

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176

103

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Organotelluriummediated living radical polymerizations (TERPs) and organostibinemediated living radical polymerizations (SBRPs) provide well-defined polymers with a variety of polar functional groups via degenerative chain-transfer polymerization. The high controllability of these polymerizations can be attributed to the rapid degenerative-transfer process between the polymer-end radicals and corresponding dormant species. The versatility of the methods allows the synthesis of AB diblock, ABA triblock, and ABC triblock copolymers by the successive addition of different monomers. This review summarizes the current status of TERP and SBRP.

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Novel Group-Transfer Three-Component Coupling of Silyltellurides, Carbonyl Compounds, and Isocyanides

Cited by 45 publications

References 37 publications

Anion-Initiated Trifluoromethylation by TMSCF₃: Deconvolution of the Siliconate–Carbanion Dichotomy by Stopped-Flow NMR/IR

Anion-Initiated Trifluoromethylation by TMSCF₃: Deconvolution of the Siliconate–Carbanion Dichotomy by Stopped-Flow NMR/IR

Free‐Radical‐Mediated Multicomponent Coupling Reactions

Development of organotellurium‐mediated and organostibine‐mediated living radical polymerization reactions

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Novel Group-Transfer Three-Component Coupling of Silyltellurides, Carbonyl Compounds, and Isocyanides

Cited by 45 publications

References 37 publications

Anion-Initiated Trifluoromethylation by TMSCF3: Deconvolution of the Siliconate–Carbanion Dichotomy by Stopped-Flow NMR/IR

Anion-Initiated Trifluoromethylation by TMSCF3: Deconvolution of the Siliconate–Carbanion Dichotomy by Stopped-Flow NMR/IR

Free‐Radical‐Mediated Multicomponent Coupling Reactions

Development of organotellurium‐mediated and organostibine‐mediated living radical polymerization reactions

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Product

Resources

About

Anion-Initiated Trifluoromethylation by TMSCF₃: Deconvolution of the Siliconate–Carbanion Dichotomy by Stopped-Flow NMR/IR

Anion-Initiated Trifluoromethylation by TMSCF₃: Deconvolution of the Siliconate–Carbanion Dichotomy by Stopped-Flow NMR/IR