Potassium Cyclopropyltrifluoroborate | CAS 1065010-87-8 | ≥98%

Suzuki–Miyaura cross-coupling with aryl and heteroaryl chlorides: Potassium cyclopropyltrifluoroborate is an organotrifluoroborate salt developed as a stable, bench-friendly surrogate for cyclopropylboronic acid in palladium-catalysed Suzuki–Miyaura cross-coupling reactions. Molander and Gormisky (J. Org. Chem. 2008, 73, 7481) demonstrated efficient coupling of this reagent with a range of aryl and heteroaryl chlorides, tolerating functional groups including ketones, esters, aldehydes, and nitriles. The trifluoroborate salt offers superior handling characteristics and shelf stability compared to cyclopropylboronic acid, which is prone to protodeboronation.

Csp³–Csp³ Suzuki coupling with benzyl chlorides: Colombel, Rombouts, Oehlrich, and Molander (J. Org. Chem. 2012, 77, 2966), working at Janssen Pharmaceutica and the University of Pennsylvania, demonstrated efficient Csp³–Csp³ bond formation between potassium cyclopropyltrifluoroborate and substituted benzyl chlorides using Pd₂(dba)₃/RuPhos catalysis. This represents a challenging bond disconnection in organic synthesis, as sp³–sp³ Suzuki couplings are significantly more difficult than conventional sp²–sp² couplings. The reaction was demonstrated at gram scale with 72% yield.

Cross-coupling with aryl mesylates: Potassium cyclopropyltrifluoroborate has been used in C–O activation of mesylated phenol derivatives via palladium catalysis. Both electron-rich and electron-deficient aryl mesylates served as effective coupling partners, with heteroaryl mesylates achieving yields up to 94%. This methodology expands the range of electrophilic partners beyond traditional aryl halides and triflates.

Synergistic photoredox/nickel catalysis: Amani and Molander (J. Org. Chem. 2017, 82, 1856) demonstrated the use of potassium cyclopropyltrifluoroborate in synergistic photoredox/nickel-catalysed coupling with acyl chlorides for dialkyl ketone synthesis. This dual-catalytic approach exploits single-electron transfer from the trifluoroborate under visible light irradiation to generate cyclopropyl radicals, which are then captured by a nickel catalyst.

Copper-catalysed Chan–Lam cyclopropylation: Derosa et al. (J. Org. Chem. 2018, 83, 3417) reported the copper-catalysed Chan–Lam coupling of potassium cyclopropyltrifluoroborate with phenols and azaheterocycles, providing a transition-metal-catalysed route to cyclopropyl ethers and N-cyclopropyl heterocycles without the need for palladium.