Friedel−Crafts Peralkylation of Benzene with ω-Chloroalkyltrichlorosilanes: One-Pot Synthesis of Polyfunctionalized Hexakis[ω-(trichlorosilyl)alkyl]benzenes

Hexakis[ω-(trichlorosilyl)alkyl]benzenes 2 [alkyl = ethyl (a), propyl (b)] containing 18
peripheral chlorine substituents on the six silicon atoms as functionalities were prepared
in 72% and 53% yields by the one-pot reaction of benzene with a 6-fold excess of
ω-chloroalkyltrichlorosilanes such as 2-chloroethyltrichlorosilane (1a) and 3-chloropropyltrichlorosilane (1b) in the presence of aluminum chloride, respectively. Single-crystal X-ray
analysis of compound 2b reveals that the 18 chlorine substituents on the six silicons are
symmetrically located on the outside. Compounds 2a,b reacted easily with methylmagnesium
bromide in diethyl ether at room temperature to give hexakis[ω-(trimethylsilyl)alkyl] in high
isolated yields of 93 and 94%.