Benzene dichloromethyl alkyl ethers

Arenes such as benzene, biphenyl and naphthalene are formylated using dichloromethyl alkyl ethers in the presence of a Lewis acid. The dichloromethyl alkyl ethers are easily prepared by the reaction of phosphorus pentachloride with alkyl formates. The most frequently used Lewis acids are titanium(IV) chloride and tin(IV) chloride. It is presumed that the electrophiles involved are alkoxychlorocarbenium... 

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