Sodium Iodide → 1-(2-(tert-butyldimethylsilyloxy)ethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

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Reaction Conditions

Reaction Steps

A mixture of 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (0.500 g, 2.58 mmol), (2-bromoethoxy)-t-butyldimethylsilane (2.211 mL, 10.31 mmol), K2CO3 (1.425 g, 10.31 mmol) and NaI (0.039 g, 0.258 mmol) in MeCN (8 mL) was heated to 70° C. for 2 days. The mixture was cooled to RT, the solid removed via filtration, rinsed with EtOAc and the filtrate washed with 50% satd. NaCl (1×). The organic layer was dried over MgSO4, concentrated to dryness and purified via silica gel chromatography (EtOAc/Hex) to afford 1-(2-((tert-butyldimethylsilyl)oxy)ethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole (574 mg, 63%) as a colorless oil. 1H NMR (400 MHz, DMSO-d6): δ 7.79 (s, 1H), 7.51 (s, 1H), 4.12 (t, J=5.4 Hz, 2H), 3.79 (t, J=5.4 Hz, 2H), 1.17 (s, 12H), 0.71 (s, 9H), −0.17 (s, 6H); MS (ESI) m/z: 353.2 (M+H+).

Provenance & Evidence