(5-Bromothiophen-2-yl)boronic Acid | CAS 162607-17-2 | ≥96%

Suzuki–Miyaura Cross-Coupling: Bifunctional Building Block

• Widely applied bifunctional heteroarylboronic acid for palladium-catalysed Suzuki–Miyaura cross-coupling — the boronic acid at C2 reacts efficiently with aryl and heteroaryl halides under standard conditions, introducing one aryl partner at C2 while the C5 bromide remains fully intact and available for a second independent transformation. This orthogonal reactivity enables modular, step-by-step construction of complex 2,5-disubstituted thiophene frameworks from a single starting material, avoiding the need for separate regioselective thiophene functionalisation steps.
• Compatible with a broad range of palladium catalyst systems, bases, and solvents including aqueous, microwave-assisted, and flow chemistry conditions. The retained C5–Br after Suzuki coupling at C2 can subsequently be engaged in a second Suzuki coupling, Sonogashira alkynylation, Buchwald–Hartwig amination, or carbonylative coupling — providing direct access to a diverse range of 2,5-disubstituted thiophene products from one bifunctional precursor.

Natural Product Synthesis: Ratanhine

• Documented Suzuki–Miyaura coupling partner in the synthesis of ratanhine — a naturally occurring acetylenic compound isolated from Krameria species with reported antifungal and antibacterial biological activity. The boronic acid at C2 provides the key C–C bond-forming step in the ratanhine synthesis, establishing the thienyl-aryl connectivity of the natural product scaffold with high efficiency and functional group tolerance.

DSSC Sensitizers & BODIPY Hybrids for Photovoltaics & Imaging

• Documented building block in Suzuki coupling reactions for the construction of benzotriazole-containing organic sensitizers for dye-sensitised solar cells (DSSCs) — benzotriazole is a widely used electron-withdrawing acceptor unit in D-π-A DSSC dye architectures, and the 5-bromothiophen-2-yl boronic acid provides the thienyl π-bridge unit that connects the donor and acceptor components of the dye scaffold via sequential cross-coupling at C2 and C5.
• Applied in the synthesis of meso-polyarylamide–BODIPY hybrid materials — BODIPY (boron-dipyrromethene) dyes are among the brightest and most photostable fluorescent dyes known, and polyarylamide–BODIPY hybrids combining the 5-bromothienyl unit are of direct interest for fluorescence imaging, photosensitiser, and light-harvesting applications. The bifunctional boronic acid enables precise incorporation of the thienyl linker between the polyarylamide backbone and the BODIPY chromophore.

Sonogashira Coupling & Ethynylarylboronate Synthesis

• Applied in microwave-assisted Sonogashira reactions exploiting the C5–Br as the electrophilic coupling partner — the boronic acid at C2 is retained intact under standard Sonogashira conditions (Pd/Cu, amine base), enabling the synthesis of 5-ethynylthiophen-2-ylboronic acid derivatives and ethynylarylboronates. These alkyne-bearing boronic acids serve as versatile bifunctional monomers for further downstream Suzuki coupling, click chemistry (CuAAC azide-alkyne cycloaddition), or incorporation into conjugated polymer backbones.

π-Conjugated Materials & Organic Electronics

• Key bifunctional monomer for the synthesis of 2,5-disubstituted thiophene-containing π-conjugated oligomers and polymers — the regiospecific C2-boronic acid / C5-bromide pattern enables regioregular Suzuki polycondensation with complementary bifunctional monomers, giving conjugated polymers with well-defined donor–acceptor alternation and maximised π–π stacking for high charge-carrier mobility in organic field-effect transistors (OFETs) and organic photovoltaics (OPVs). The thiophene ring is present in approved drugs including clopidogrel and rivaroxaban, making this compound equally relevant to pharmaceutical fragment synthesis alongside its materials science applications.