Regiodivergent halogenation of vinylogous esters: one-pot, transition-metal-free access to differentiated haloresorcinols.

We report an efficient method for the regiodivergent synthesis of halogenated resorcinol derivatives using readily available vinylogous esters and sulfonyl halide halogen donors. Either the 4- or 6-haloresorcinol isomer is accessible from a common precursor. In contrast to conventional oxidants for arene halogenation, mild sulfonyl halides allow broad functional group compatibility. The strategy inherently differentiates the two resorcinol oxygen atoms and enhances the potential for complex molecule synthesis.