Copper-Catalyzed Arylation of Chlorosilanes with Grignard Reagents

Abstract

Nucleophilic substitution reactions of chlorosilanes with aryl Grignard reagents take place efficiently in the presence of copper(I) iodide to afford tetraorganosilanes.

Palladium-Catalyzed Cross-Coupling of Monochlorosilanes and Grignard Reagents

“…Palladium catalysis allows full conversion of bulky aryl groups to form encumbered silanes ( 15–16 ). The addition of ortho -tolyl magnesium bromide to prepare 15 compares well with the prior catalytic conditions reported by Oshima; 19 however, those studies did not report the addition of larger Grignard reagents, such as mesityl magnesium bromide. These examples demonstrate the ability of this catalytic system to accommodate highly sterically hindered coupling partners to form silanes that are otherwise inaccessible.…”

“…19 However, these reactions are believed to proceed via nucleophile activation, and not via activation of the Si–Cl bond. Moreover, none of those conditions exhibited any advantage in the case of alkyl Grignard reagents.…”

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

“…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.…”

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

The Chemistry of Heterasumanenes

“…Heating a mixture of triphenylene and butyllithium in hexane and TMEDA ( N , N , N ′, N ′‐tetramethylethylenediamine) afforded 1,12‐dilithiotriphenylene, which reacted with dichlorodimethylsilane to provide triphenylenosilole 1 in 31% yield. The yield of 1 was improved to 50% using copper cyanide as a catalyst (Scheme ) . The next step was to introduce the second silylene bridge into 1 .…”