TheWagner-Jauregg reaction is a classicorganic reaction inorganic chemistry, named afterTheodor Wagner-Jauregg [de] (son ofJulius Wagner-Jauregg), describing the doubleDiels–Alder reaction of 2 equivalents ofmaleic anhydride with a 1,1-diarylethylene. Afteraromatization of the bis-adduct, the ultimate reaction product is anaphthalene compound with onephenyl substituent.[1][2]
The reaction is unusual in that the anhydride reacts with the aromatic ring. The presence of the additional alpha-phenyl group on the phenylethene (the styryl group) activates the styryl for a Diels–Alder reaction even at the expense of its aromaticity. In contrast, unactivatedstyrene reacts instead at thealkene alone via a linear polymerization reaction.Styrene maleic anhydride copolymer is formed, retaining the aromaticity of the styrene.
The Diels–Alder product can be re-aromatized using elementalsulfur at high temperature, followed by a second rearomatization bydecarboxylation withbarium hydroxide andcopper:[3]
