Potassium (5-Bromothiophen-2-yl)trifluoroborate | CAS 1239370-98-9 | ≥98%

Suzuki–Miyaura Cross-Coupling: Trifluoroborate Advantages

• Applied as a bench-stable, air-stable alternative to the corresponding boronic acid in palladium-catalysed Suzuki–Miyaura cross-coupling — the trifluoroborate undergoes in situ hydrolysis to the active boronic acid species under aqueous base conditions, enabling standard Suzuki coupling at the C2 position of the thiophene ring while the C5 bromide remains intact. Unlike boronic acids, potassium aryltrifluoroborates exist exclusively as monomeric species and do not form boroxine anhydrides — enabling precise stoichiometric control and consistent reactivity across batches, a significant advantage for small-scale, automated, and parallel synthesis workflows.
• Compatible with a broad range of palladium catalyst systems and base/solvent combinations including aqueous, microwave-assisted, and flow chemistry conditions — the crystalline salt form provides superior handling properties, shelf stability, and ease of weighing compared to hygroscopic boronic acids, making it the preferred reagent form for high-throughput screening library synthesis.

Bifunctional Monomer: Sequential Cross-Coupling

• The defining synthetic feature of this compound is its dual functionality — the trifluoroborate at C2 and the aryl bromide at C5 are independently reactive under different metal-catalysed conditions, enabling step-by-step construction of complex thiophene-containing scaffolds from a single bifunctional starting material. In a typical sequence, the trifluoroborate is engaged first under Suzuki conditions to introduce one aryl partner at C2, and the C–Br is subsequently used for a second Suzuki coupling, Buchwald–Hartwig amination, carbonylative coupling, or other palladium-catalysed transformation at C5 — providing direct, modular access to 2,5-disubstituted thiophene frameworks that are otherwise difficult to assemble regioselectively.
• Applied as a bifunctional monomer in Suzuki polycondensation for the synthesis of alternating π-conjugated copolymers — the trifluoroborate and C–Br termini allow iterative chain growth in a defined sequence, enabling precise control of the regiochemistry and composition of the resulting conjugated polymer backbone, which directly determines its optical bandgap, charge-carrier mobility, and device performance.

π-Conjugated Materials & Organic Electronics

• Key bifunctional monomer for the construction of thiophene-containing π-conjugated oligomers and polymers for organic semiconductor applications — 2,5-disubstituted thiophene units are among the most important repeating units in organic field-effect transistors (OFETs), organic photovoltaics (OPVs), and electrochromic devices. The precise regiochemical control offered by the C2-trifluoroborate / C5-bromide combination enables regioregular polymer synthesis that maximises π–π stacking and charge-transport efficiency in thin-film devices.
• Applied in the synthesis of donor–acceptor (D-A) conjugated polymers where the electron-rich thiophene unit is paired with electron-deficient acceptor monomers — the sequential coupling strategy enabled by this bifunctional building block allows systematic variation of the donor–acceptor ratio and sequence for bandgap engineering in solution-processable organic photovoltaic materials.

Medicinal Chemistry & Pharmaceutical Building Blocks

• Applied in the synthesis of 2,5-disubstituted thiophene-containing pharmaceutical scaffolds — the thiophene ring is present in approved drugs including clopidogrel, ticlopidine, olanzapine, and rivaroxaban, and the 2,5-disubstituted substitution pattern is particularly prevalent in kinase inhibitors and GPCRs ligands where the thiophene serves as a planar, sulfur-containing bioisostere for phenyl or furan rings. The trifluoroborate / C–Br bifunctionality provides a streamlined two-step coupling route to these scaffolds without requiring separate regioselective functionalisation of the thiophene ring.