Pd-Catalyzed Thiotritylation Cross-Coupling of Aryl Bromides and Iodides to Access Sulfur Functional Groups

Sulfur-containing functional groups (SFGs) are increasingly important for modern medicinal chemistry and their large structural diversity provides many opportunities for lead optimization. In an effort to simplify the access to the full set of SFGs, we report herein a versatile strategy utilizing (hetero)aryl trityl sulfides (ArSCPh₃) as the common precursors. We developed a mild and high yielding Pd-catalyzed thiotritylation cross-coupling methodology to afford ArSCPh₃ compounds from (hetero)aryl bromides and iodides. Efficient chemoselective derivatizations provided access to eight different SFGs and sulfur(VI) fluorine exchange (SuFEx) hubs, which open up further downstream derivatizations towards the full set of SFGs. Thereby obtainable sulfur motifs include aryl sulfur pentafluorides (ArSF₅), aryl tetrafluoro-λ⁶-sulfanyl chlorides (ArSF₄Cl), aryl sulfonimidoyl fluorides (ArS(O)(NR)F), aryl sulfonyl fluorides (ArSO₂F), aryl sulfonic acids (ArSO₃H), and aryl sulfinyl fluorides (ArSOF), which are all valuable functional groups in modern drug discovery.