Arylboronic acids tetrafluoroborate

Resin-bound benzylic thioethers can be converted into sulfonium salts by S-alkyla-tion with triethyloxonium tetrafluoroborate. These sulfonium salts react with palladium ) complexes to yield benzylpalladium complexes, which undergo Suzuki coupling with arylboronic acids (Entry 7, Table 3.48),... 

Darses, S. Jeffery, T. Genet, J.P. Brayer, J.L. Demoute, J.P. (1996) Cross-coupling of arenediazonium tetrafluoroborates with arylboronic acids catalyzed by palladium. Tetrahedron Lett., 51, 3857-60. 

The estrone-derived arylboronic acid (1.0 equiv) and CH Clj (0.075 M) were combined in an oven-dried round-bottom flask equipped with a stir bar. The mixture was cooled to 0 °C, BFj-OEtj (1.10 equiv) was added, and the mixture was stirred for 10 min. 2-(Diacetoxyiodo) mesitylene (1.05 equiv) was then added as a solution in CH Cl (0.33 M), and the mixture was warmed to room temperature and stirred for 2h. The reaction was quenched by the addition of saturated aqueous NaBF. After 30 min of vigorous stirring, the aqueous layer was extracted with CH Clj (2x). The combined organic layers were dried over MgSO, filtered, and concentrated under vacuum. Et O was added to the residual solid, and the diaryliodonium tetrafluoroborate (73%) was collected via filtration, washed with Et O, dried under vacuum overnight, and stored in a dry box under until use. 

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