Formylation and dichloromethylation as alternative directions of rieche reaction. A novel to the synthesis of sterically hindered aromatic dialdhydes

Abstract

A previously unknown direction of Rieche reaction has been found: formylation of mesitylene, m-xylene, and durene with dichloromethyl methyl ether in the presence of aluminium trichloride and, to lesser extent, of titanium tetrachloride give the respective benzylidene dichlorides besides aldehydes. A novel approach to the synthesis of sterically hindered aromatic dialdehydes has been offered which involves the transformation of a monoaldehyde into the corresponding benzylidene dichloride, Rieche formylation of the latter, and hydrolysis of dichloromethyl aldehyde formed.