Benzylation of arenes with benzyl ethers promoted by the in situ prepared superacid BF3-H2O

An efficient and environmentally friendly benzylation of arenes with benzyl ethers as benzyl donors using BF3-Et2O to generate in situ the superacid BF3-H2O as an efficient promotor has been described. A wide variety of functional groups have been investigated and found to be compatible to give the desired diaryl-methanes in yields of up to 99%. The crucial role of the moisture content in this transformation has been demonstrated by detailed investigations.