SYNTHESIS AND STRUCTURES OF SILYL-GROUP-CONTAINING HEXAALKYLATED BENZENES

Friedel-Crafts alkylation of vinyldichloromethysilane to benzene in th e presence of aluminum chloride catalyst at room temperature gave hexa kis((dichloromethylsilyl)ethyl)benzene (1) in 56% yield, along with sm all 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 . 2C H(2)Cl(2)) and hexakis(dibenzylmethylsilyl)ethyl)benzene (11 . 2CHCl(3 )) have been determined by X-ray diffraction studies. Each dichloromet hane and chloroform molecule formed C-H ... aryl hydrogen bonds, one a bove and one below, to the ring centroid. The distances between the ca rbon and the ring centroid were 3.469 and 3.466 Angstrom for CH2Cl2 an d CHCl3, respectively.