Cesium carbonate → tert-Butyl 2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl)acetate

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Reaction Conditions

Reaction Steps

To a solution of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (1.5 g, 0.0077 mol) in DMF (25 mL) was added 2-bromoacetic acid 1,1-dimethylethyl ester (1.2 mL, 0.0085 mol) and cesium carbonate (3.8 g, 0.012 mol). The suspension was stirred at 90° C. overnight. The reaction mixture was cooled to RT and partitioned with ethyl acetate and water. The organic layer was washed with water, brine, and dried over MgSO4. The solution was concentrated to afford the desired compound (2.0 g, 84%). Analytical LC/MS: (M+H)+=309.4.

Provenance & Evidence