Cesium carbonate → 1-(Tetrahydro-2H-pyran-4-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

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Reaction Conditions

Reaction Steps

In 8 mL of N,N-dimethylformamide were combined 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (0.75 g, 3.87 mmol), tetrahydro-2H-pyran-4-yl methanesulfonate (1.04 g, 5.80 mmol), and Cs2CO3 (2.01 g, 6.18 mmol) in a glass bomb and then sealed under nitrogen and heated to 100° C. After one hour the reaction was cooled and water was added to dissolve all solids. The solution was diluted with water and then extracted with EtOAc (250 mL). The organic layer was then washed with water and brine. The combined aqueous layer was then extracted with EtOAc (200 mL). The organic layers were combined, dried over MgSO4, filtered, and concentrated under reduced pressure. The crude material was dried overnight on high vacuum. The crude was purified by way of silica gel chromatography eluting with a gradient of 15-25% EtOAc in DCM to afford 1-(tetrahydro-2H-pyran-4-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (0.176 g, 0.633 mmol, 16.4% yield). MS (apci) m/z=279.2 (M+H).

Provenance & Evidence