2-Methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → 1-(3-{[tert-butyl(dimethyl)silyl]oxy}cyclobutyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

Over the course of 5 minutes, a 2.00 M solution of isopropylmagnesium chloride in THF (0.13084 mL, 0.26168 mmol) was added dropwise to an ice cooled solution of 1-[3-(tert-butyl-dimethyl-silanyloxy)-cyclobutyl]-4-iodo-1H-pyrazole (Compound 100B, 30.00 mg, 0.07930 mmol) in THF (0.33 mL). The reaction mixture was stirred at 0° C. for another hour. 2-Methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.057933 mL, 0.33939 mmol) was added at 0° C. and then the mixture was stirred at rt for another hour. The reaction mixture was cooled back down to 0° C., quenched with saturated aqueous NH4Cl, and extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4, filtered, and concentrated in vacuo to dryness, giving the title compound as a colorless oil. Compound was taken on for the next step without further purification. MS (ES+): m/z 379.04 (100) [MH+]; HPLC: tR=3.85 min (ZQ3, polar—5 min).

Provenance & Evidence