Nucleophilic catalysis of organosilicon substitution reactions

Lennon, Patrick J.; Mack, David P.; Thompson, Quentin E.

doi:10.1021/om00106a043

Cited by 55 publications

(29 citation statements)

References 2 publications

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“…The use of a long alkylmagnesium bromide as Grignard reagent has been reported in one case [8]. However, reaction between long alkylmagnesium bromide and tetrahedral silicon is problematic [12].…”

Section: General Synthetic Strategymentioning

confidence: 99%

Carbosilane Dendrimers – Synthesis, Functionalization, Application

Schlenk

Frey

1999

Monatshefte fuer Chemie

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Summary. This micro-review summarizes historical and recent developments in synthesis, functionalization, and characterization of carbosilane dendrimers. These compounds are the most important among the heteroatom-based dendrimers at present due to the flexibility of the synthetic route and to their chemical stability which allows versatile further functionalization. Synthesis as well as application potential of carbosilane dendrimers for catalysis, host-guest chemistry, liquid crystals, and novel polymer topologies is discussed.Keywords. Carbosilane; Dendrimer; Catalysis; Liquid crystals; Hyperbranched.Carbosilandendrimere -Synthese, Funktionalisierung und Anwendung Zusammenfassung. Der vorliegende Mikroreview faSt historische und aktuelle Entwicklungen bezuglich Synthese, Funktionalisierung und Charakterisierung von Carbosilandendrimeren zusammen. Wegen der Variabilitat der Syntheseroute und ihrer chemischen Stabilitat, die weitere Funktionalisierung erlaubt, zahlen diese Verbindungen zu den wichtigsten unter den Heteroatomdendrimeren. Synthese und Potential der Carbosilandendrimere auf den Gebieten der Katalyse, Wirt-Gast-Chemie, Flussigkristalle und neuer Polymertopologien werden diskutiert.

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Section: General Synthetic Strategymentioning

confidence: 99%

Carbosilane Dendrimers – Synthesis, Functionalization, Application

Schlenk

Frey

1999

Monatshefte fuer Chemie

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“…6 Alkylations with primary and aryl nucleophiles are known. 7,8 As has been recently noted, the addition of secondary organ-ometallic reagents to silyl electrophiles is rarely effective. 9,10 In fact, to our knowledge, over the past seventy years only five isolated examples with secondary nucleophiles have been reported in the chemical literature.…”

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confidence: 99%

“…Prior catalytic methods, which have proven effective with primary and aryl nucleophiles, are ineffective in coupling secondary alkyl groups. 6a, 7–8 …”

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confidence: 99%

Palladium-Catalyzed Cross-Coupling of Silyl Electrophiles with Alkylzinc Halides: A Silyl-Negishi Reaction

2017

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“…7 The key roles of the penta-or hexa-coordinate silicon compounds have been suggested in both cases. Further studies on the metal cyanide effect on other reactions are currently in progress in our laboratory.…”

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Stereochemical Control of the Reaction of Chlorosilane with Methyllithium by the Addition of Metal Cyanide: Inversion by Potassium Cyanide and Retention by Copper(I) Cyanide

Tamao¹,

Tsuji²,

Toshimitsu³

2001

Synlett

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Abstract:In the 1,4-dichlorotetrasilane derivative composed of disilane units bearing two pentamethylene tethers, the substitution of a chlorine atom on the silicon atom by the methyl group during the reaction with methyllithium mainly proceeds with inversion of configuration of the silicon atoms, (1) the yield being dramatically improved by the addition of potassium cyanide, and (2) the stereochemistry being changed to retention of configuration by the addition of copper(I) cyanide.Key words: bicyclic compounds, copper(I) cyanide, organosilicon compounds, potassium cyanide, stereoselectivityIn our recent study on the photophysical properties of conformationally controlled oligosilanes using disilane units configurationally constrained into syn or anti by two pentamethylene tethers (Figure), 1 we reported the synthesis of the tetrasilane compound anti,anti-dimer 2 (shown in Scheme) by the reaction of syn,syn-1,4-dichlorotetrasilane 1 with methyllithium with inversion of configuration at both silicon centers.2 Since the yield of this reaction was not satisfactory (30%), we have been trying to optimize the reaction conditions and found the following unprecedented effect by metal cyanides: (1) the yield and the selectivity for 2 are dramatically increased by the addition of potassium cyanide to the reaction mixture, and (2) the stereoselectivity is completely changed from inversion to retention by the change in the countercation of the cyanide salt added, namely from potassium to copper(I). These results are reported in this paper. 6:1, 0°C -r.t., 12 h) revealed that, in addition to the anti,anti-dimer 2 in 30% yield, the anti,syn-dimer 3 arising from the substitution reaction with retention of configuration at one silicon center was also formed in 15% yield (Scheme and Table, entry 1). With the addition of potassium cyanide to this reaction mixture, the yields of 2 were dramatically increased (entries 2 and 3) accompanied by the formation of a small amount of syn,syn-dimer 4, the yields of the anti,syn-dimer 3 remaining nearly the same. Thus, the total number of reactions with inversion of configuration N(inv) and that with retention N(ret) at each silicon center 3 were only slightly changed, keeping the N(inv)/N(ret) at 4.8: 1 ~ 6.8: 1 (Figure 1, none and KCN). Table Yields In contrast, in the presence of a catalytic amount of copper(I) cyanide (0.4 molar amount), the syn,syn-dimer 4 was found to be the major product (50% yield) accompanied by the formation of the anti,syn-dimer 3 (18% yield) (entry 4). The structure of 4 was unambiguously confirmed by X-ray crystallographic analysis as shown in Si Si Cl Si Si Cl Si Si Me Si Si Me Si Me Si SiMe Si Si SchemeThis document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.

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Nucleophilic catalysis of organosilicon substitution reactions

Abstract: Catalytic quantities of cyanide or thiocyanate ions are shown to facilitate the substitution of silyl chlorides by Grignard reagents and dialkylmagnesium reagents, to afford high yields of tetraalkyl-and tetraarylsilanes under extremely mild conditions.

Cited by 55 publications

References 2 publications

Carbosilane Dendrimers – Synthesis, Functionalization, Application

Carbosilane Dendrimers – Synthesis, Functionalization, Application

Palladium-Catalyzed Cross-Coupling of Silyl Electrophiles with Alkylzinc Halides: A Silyl-Negishi Reaction

Stereochemical Control of the Reaction of Chlorosilane with Methyllithium by the Addition of Metal Cyanide: Inversion by Potassium Cyanide and Retention by Copper(I) Cyanide

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