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).