The catalytic Friedel–Crafts alkylation reaction of aromatic compounds with benzyl or allyl silyl ethers using Cl2Si(OTf)2 or Hf(OTf)4

The Friedel–Crafts alkylation reaction of various aromatic compounds with benzyl or allyl silyl ethers is effectively promoted under mild reaction conditions using Lewis acid catalysts. A mixture of the desired phenyltolylmethanes is obtained in 80% yield from toluene with benzyl dimethylsilyl or trimethylsilyl ether at 50°C in the presence of a catalytic amount of Cl2Si(OTf)2 or Hf(OTf)4.