4,4,6-Trimethyl-2-vinyl-1,3,2-dioxaborinane: An Efficient and Selective 2-Carbon Building Block for Vinylboronate Suzuki-Miyaura Coupling Reactions

Abstract

An extremely simple and efficient palladium-catalyzed coupling procedure for the synthesis of functionalized styrenes and dienes is utilized to demonstrate how 4,4,6-trimethyl-2-vinyl-1,3,2-dioxaborinane can be employed to selectively undergo Suzuki-Miyaura coupling with a range of halide substrates.

Key words

Suzuki-Miyaura coupling - palladium(0) - vinylboronate ester - chemoselectivity

References

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7

Typical Procedure, Conditions A.
To an oven dried Schlenk-like tube under argon was added Pd(PPh₃)₄ (39 mg, 33.8 µmol) and t-BuOK (91 mg, 0.81 mmol), followed by THF (6 mL), substrate (0.675 mmol) and boronate 4 (0.125 g, 0.81 mmol). The tube was heated at 67 °C for 24 h before cooling, dilution with Et₂O (30 mL) and filtration through Celite. This solution was treated with undecane (50 µL, 37.5 mg) and a portion was analyzed by GC. ¹H NMR analysis to determine the Heck: Suzuki ratio, which was carried out after evaporation to give the crude product. Purification was carried out by silica gel column chromatography (hexane as eluant).