Synthesis and structures of silyl-group-containing hexaalkylated benzenes

Abstract

Friedel-Crafts alkylation of vinyldichloromethysilane to benzene in the presence of aluminum chloride catalyst at room temperature gave hexakis((dichloromethylsilyl)ethyl)benzene (1) in 56% yield, along with small amounts of less alkylated products. 1 was easily converted to the corresponding compounds, C-6(CH2CH2SiMeR2)(6); (5 (R = OCH3), 6 (R = H), 7 (R = CH3), 8 (R = vinyl), 9 (R = allyl), 10 (R = ethynyl), and 11 (R = benzyl)) by reaction with the appropriate nucleophilic reagents. The molecular structures of hexakis((methylsilylethyl)benzene (6) and the solvent adducts of hexakis(( trimethylsilyl)ethyl)benzene (7 . 2CH(2)Cl(2)) and hexakis(dibenzylmethylsilyl)ethyl)benzene (11 . 2CHCl(3)) have been determined by X-ray diffraction studies. Each dichloromethane and chloroform molecule formed C-H ... aryl hydrogen bonds, one above and one below, to the ring centroid. The distances between the carbon and the ring centroid were 3.469 and 3.466 Angstrom for CH2Cl2 and CHCl3, respectively.