Chemo-orthogonal biaryl formation via Pd/Cu-catalyzed decar-boxylative coupling of arylthianthrenium salts

Abstract

Thianthrenium groups are versatile synthetic handles that can be selectively installed into complex arenes via C–H functionalization. We disclose a bimetallic Pd/Cu system that enables their substitution by functionalized (hetero)arenes through a cooperatively catalyzed decarboxylative coupling with aromatic carboxylates. The reaction makes use of widely available substrates and is broadly applicable, even to drug-like substrates. By exploiting a reactivity mode that is orthogonal to classical cross-couplings, this method allows the introduction of (hetero)arenes bearing typical anchor groups for subsequent derivatization—namely bromide, triflate, nitro, and even iodide groups. This streamlines diversification of the (hetero)biaryl products, significantly expanding the utility of thianthrenium salts as synthetic lynchpins.