Potassium Carbonate → 1-(methoxymethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

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Reaction Conditions

Reaction Steps

4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (10.00 g, 51.5 mmol) was dissolved in acetonitrile (40 mL) and stirred at 35° C. for 5 min under nitrogen atmosphere then cooled to room temperature. Iodomethyl methyl ether (21.83 mL, 258 mmol) and potassium carbonate (35.6 g, 258 mmol) were added and the resulting mixture was stirred at 35° C. for 3 h then cooled to room temperature. The insoluble material was filtered off and the filtrate was concentrated in vacuo. The residue was dissolved in EtOAc and the organic phase was washed with water, dried over MgSO4 and concentrated in vacuo. Purification of the residue by SP4 using a 100 G silica cartridge (gradient: 0 to 50% AcOEt in hexanes) gave 1-[(methyloxy)methyl]-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (6.45 g, 50% pure by LCMS, 26%) as a yellow liquid which was used in the next step without further purification.

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