Enantioselective Desymmetrization of Bisphenol Derivatives by Organocatalytic Sulfonylation

Chiral 1,1‐diarylalkanes were synthesized by enantioselective desymmetrization of bisphenol derivatives through an organocatalytic sulfonylation reaction. The methodology involves the selective sulfonylation of one enantiotopic hydroxy group of a bisphenol using a sulfonyl chloride with a chiral thiourea catalyst in a CHCl₃/H₂O system under basic conditions. The resulting products were obtained in good to high yields (up to 97%) with high enantioselectivity (up to 90.5:9.5 er). Remarkably, compounds that were almost enantiomerically pure could be obtained from the mother liquor after crystallization