Complementary Site-Selective Sulfonylation of Aromatic Amines by Superacid Activation

Under superacidic conditions, aniline and indole derivatives are sulfonylated at low temperature with easy-to-access arenesulfonic acids or arenesulfonyl hydrazides. By modification of the functional-group directing effect through protonation, this method allows nonclassical site functionalization by overcoming innate regioselectivity electrophilic aromatic substitution. This superacid-mediated sulfonylation arenes is complementary to existing methods can be applied, protection late-stage site-selective natural alkaloids active pharmaceutical ingredients.