From Maleic Anhydrides to Substituted Resorcinols

Abstract

Symmetrically substituted maleic anhydrides react at -78 °C with lithiomethyl phenyl sulfone to give the corresponding 4-hydroxy-4-(phenylsulfonylmethyl)-buteno-4-lactones, which, on treatment with Mel/K₂CO₃ in acetone, are transformed into 5-methyl-5-phenylsulfonylcyclopent-2-ene-1,4-diones. These compounds rearrange in the presence of an excess of lithiomethyl phenyl sulfone at -78 °C and then butyllithium at -5 °C to ambient temperature into 4,5-disubstituted 6-methyl-2-phenylsulfonyl-resorcinols.