No Detours: Palladium-Catalyzed Oxidative C-H/C-H Cross-Couplings of Heteroarenes

Abstract

Recent developments in the field of intermolecular cross-couplings between heteroarenes through dual C-H bond cleavage under oxidative conditions are reviewed. The use of palladium catalysts allows for regioselective carbon-carbon bond formations between important classes of heteroarenes without the need to prefunctionalize the positions that shall be linked.

Key words

catalysis - C-C bond formation - heteroarylation - palladium - regioselectivity

References and Notes

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23

The presence of Ag⁺ ions also affects the selectivity for the cross-coupling reaction. As investigated in detail for the reaction of benzothiazole with 4,5-dimethylthiazole, the cross-coupling is strongly favored (92% yield) in the presence of AgF (2 equiv; Scheme  [8] ). Without AgF but under otherwise identical reaction conditions, a mixture of the cross-coupling product (41%) and both homodimers, i.e., bi(4,5-dimethyl)thiazolyl (43%) and bi(benzothiazolyl) (15%) were produced.