Deoxygenative Chlorination of Aldehydes and Alcohols with Dichloromethyl Methyl Ether and TiCl4

Abstract Here, we report highly efficient deoxygenative chlorination of aldehydes and alcohols with a dichloromethyl methyl ether and TiCl 4 system. The method converts various aldehydes and alcohols into the desired geminal dichlorides or chlorides with good to excellent yields (up to 99 %). Combined with a subsequent Rieche formylation step using the same reagent system, this method provides an efficient approach for synthesis of aromatic dialdehydes. This strategy involves deoxy‐chlorination of the aryl aldehydes followed by a second formylation of more activated benzal chloride derivatives. Dialdehydes can be easily obtained by hydrolyzing the corresponding of dichloromethyl derivative.