Cesium carbonate → ethyl 2-methyl-2-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl)propanoate

Participants

Reaction Conditions

Reaction Steps

To a stirred mixture of 4-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (5.0 g, 25.8 mmol) and Cesium carbonate (12.6 g, 38.7 mmol) in dry DMF (50 ml) was added 2-Bromo-2-methyl-propionic acid ethyl ester (5.5 g, 28.2 mmol). The reaction mixture was heated at 90° C. under N2 for 18 h, before being allowed to cool to room temperature. The mixture was partitioned between EtOAc and H2O, the organic layer separated and washed with H2O (×2) and brine (×1), dried (Na2SO4), filtered and the solvent removed in vacuo. This afforded the crude product as a yellow oil, which was used directly in the next step (4.7 g, 15.3 mmol).

Provenance & Evidence