Synthesis of cinnamaldehydes, esters of cinnamic acids and acylals of cinnamaldehydes by oxidation of arylpropenes with 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ)

Abstract

Abstract 1-Arylpropenes and 3-arylpropenes give cinnamaldehydes (yield≈ 80%) on oxidation with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in the presence of water. The conversion to aldehydes is promoted by electron-donating groups at the aromatic ring. On DDQ oxidation in the presence of methanol, methyl esters of cinnamic acids are the predominant products. DDQ oxidation of 1- or 3-(3,4-dimethoxyphenyl)-1-propene in the presence of acetic acid gives an acylal [the diacetate of ( E )-3-(3,4-dimethoxyphenyl)-2-propene-1,1-diol].