Transition-metal-free glycosyl sulfonation of diaryliodonium salts with sodium glycosyl sulfinate: an efficient approach to access glycosyl aryl sulfones

Abstract

Glycosyl aryl sulfones have gained significant attention due to their diverse range of biological activities. However, a straightforward synthesis under mild conditions remains a challenging endeavor. This work presents the first transition-metal-free glycosyl sulfonation, employing a readily prepared sodium glycosyl sulfinate in conjunction with diaryliodonium salts. The method is compatible with various sugar substrates including unprotected sugar derivatives. Notably, the transfer of an aryl moiety in unsymmetric diaryl iodonium salts is chemoselectively achieved by utilizing an anisyl or TMP fragment as a dummy ligand. Preliminary mechanistic studies suggest that the reaction may proceed through an intramolecular S_NAr process with a four-membered ring transition state.