Formation of 2-(Phenylsulfonyl)resorcinols (=2-(Phenylsulfonyl)benzene-1,3-diols) from Symmetrically Substituted Maleic Anhydrides (=Furan-2,5-diones)

Treatment of symmetrically substituted maleic anhydrides (=furan-2,5-diones) 6 with lithium (phenylsulfonyl)methanide, followed by methylation of the adduct with MeI/K2CO3 in acetone, give the corresponding 4,5-disubstituted 2-methyl-2-(phenylsulfonyl)cyclopent-4-ene-1,3-diones 8 (Scheme 3). Reaction of the latter with lithium (phenylsulfonyl)methanide in THF (−78°) and then with 4 mol-equiv. BuLi (−5° to r.t.) leads to 5,6-disubstituted 4-methyl-2-(phenylsulfonyl)benzene-1,3-diols 9 (Scheme 4).