Pd(II)/Cu(I) Co-catalyzed Dual C–H Functionalization of Indoles at C2 and C3 Positions Using Bifunctional Arylsulfonyl Reagents

A Pd(II)/Cu(I) co-catalyzed dual C-H functionalization strategy enables the one-pot synthesis of C2/C3-difunctionalized indoles using arylsulfonyl reagents. In this method, Cu(I) reduces S(VI) reagents to generate arylsulfonyl radicals, which react with Pd(II) to form electrophilic Ar-Pd(III) intermediates. These intermediates regioselectively arylate indoles at the C2 position, followed by Cu(II)-mediated C-H functionalization at the C3 position, to deliver the final products. This synergistic method enhances efficiency, reduces waste, and streamlines complex indole functionalization.