Chemo-Orthogonal Biaryl Formation via Pd/Cu-Catalyzed Decarboxylative 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.