2-Methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → 4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl)-1lambda6-thiane-1,1-dione

Participants

Reaction Steps

Isopropylmagnesium chloride (2.0 M in THF, 1.23 mL, 2.45 mmol) was slowly added to a solution of 4-(4-iodo-1H-pyrazol-1-yl)tetrahydro-2H-thiopyran 1,1-dioxide (0.50 g, 1.533 mmol) in THF (6.0 mL) at −10° C. The reaction mixture was warmed to room temperature and stirred for 1 h. The reaction was then cooled to 0° C., 2-methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (0.402 mL, 2.45 mmol) was added, and the reaction stirred at room temperature for an additional 1.5 h. The reaction solution was then concentrated in vacuo to remove the THF. The crude solid was dissolved in ether (200 mL) and filtered. The filtrate was slowly concentrated until a white precipitate formed. The solution was allowed to stand for 2 h, and the precipitate was filtered and dried in vacuo to afford 4-(4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazol-1-yl)tetrahydro-2H-thiopyran 1,1-dioxide (0.34 g, 68%) as a white powder. MS (ESI, pos. ion) m/z 327 [M+H]+.

Provenance & Evidence