Tri-tert-butylphosphonium tetrafluoroborate

A solution of 0.3 mL of water and 3 mL of dioxane in a 5-mL, two-necked, round-bottomed flask was purged with nitrogen and stirred for 10 min at 25 °C. [Rh(cod)Cl]2 (3.0 mg, 0.006 mmol of Rh), tri-tert-butylphosphonium tetrafluoroborate (3.5 mg, 0.0132 mmol), and potassium fluoride (23.3 mg, 0.40 mmol) were added to the solution and stirred at 25 °C for 10 min. To the bright yellow solution was added Ihe alkene 84, followed by addition of the boronate ester 83 (56.0 mg, 0.20 mmol), and the reaction mixture was stirred at 80 °C for 3 h. The reaction was quenched with brine, and the aqueous layer was extracted with Et20 (three times). The combined organic layers were dried with anhydrous MgS04, filtrated, and concentrated in vacuo. The Final product 85 was obtained in 84% yield. 

Handling, Storage, and Precautions tri-tert-butylphosphonium tetrafluoroborate is indefinitely stable as a solid and in solution and requires no special handling. This compound is considered nonhazardous. Protection from oxygen is required in the presence of base, as the highly air-sensitive tri-tert-butylphosphine will be formed. 

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