Trimethyl borate → {5-[(4-Fluorophenyl)carbonyl]-2-(phenoxymethyl)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-3-yl}boronic acid

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Reaction Conditions

Reaction Steps

A 1.3M solution of isopropylmagnesium chloride lithium chloride complex solution (39 mL, 0.5 mmol) was added to a stirred solution of (4-fluoro-phenyl)-(3-iodo-2-phenoxymethyl-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazin-5-yl)-methanone (0.2 g, 0.42 mmol) in THF (4 mL) at −78° C. and under N2. The mixture was stirred at −78° C. for 1 minute and then trimethyl borate (0.093 mL, 0.84 mmol) was added. The mixture was stirred −78° C. for 30 minutes and at room temperature for 1 hour. The mixture was diluted with water and extracted with AcOEt. The organic layer was separated, dried (MgSO4), filtered and the solvents evaporated in vacuo to yield {5-[(4-fluorophenyl)carbonyl]-2-(phenoxymethyl)-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrazin-3-yl}boronic acid (0.21 g, 56% yield) as a yellow oil that was used in the next step without further purification.

Provenance & Evidence