Potassium Vinyltrifluoroborate | CAS 13682-77-4 | ≥95%

Potassium Vinyltrifluoroborate (potassium trifluoro(vinyl)borate, vinyl-BF3K) is a monomeric, air- and moisture-stable crystalline salt for vinyl transfer in palladium- and other metal-catalysed C–C bond formation. Free vinylboronic acid is prone to protodeboronation and equilibrates with its boroxine, leaving it neither stable nor of fixed stoichiometry, while vinyllithium and vinyl-Grignard reagents are pyrophoric and poorly tolerant of functional groups. The trifluoroborate carries none of these liabilities: it is weighed to an exact stoichiometry and handled in air.

Applications and Reactions

• Suzuki–Miyaura vinylation: under palladium catalysis it transfers a vinyl group to aryl and heteroaryl halides and triflates, giving styrenes and vinyl heterocycles — building blocks for pharmaceutical and materials synthesis.
• Controlled boron release: as a masked boronic acid, it hydrolyses only slowly under the aqueous, basic coupling conditions, supplying the active vinylboron species at the low concentration that clean transmetalation needs.
• Vinylation of arenediazonium salts: palladium-catalysed coupling with arenediazonium salts, often base- and ligand-free, gives styrenes rapidly, and sequential Suzuki–Heck reactions extend this to stilbenes.
• Beyond cross-coupling: potassium organotrifluoroborates, including alkenyl members, undergo rhodium-catalysed 1,4-addition to enones (for example, isopropenyltrifluoroborate to cyclic enones), illustrating reactivity of the BF3K family beyond classical coupling.
• Polymer and π-conjugated materials: the vinyl unit is built into poly(arylenevinylene)-type conjugated polymers and into materials for dye-sensitised solar cells and photonic crystals.

Further Reading

For practical guidance on choosing boronic acids, boronate esters, and organotrifluoroborates as cross-coupling partners, see the NorrChemica Lab Journal article: Choosing Your Boron Source for Suzuki–Miyaura Coupling.