Sodium hydride → 3,5-Dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1-((2-(trimethylsilyl)ethoxy)methyl)-1H-pyrazole

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Reaction Steps

A stirred suspension of 3,5-dimethyl-4-(4,4,5,5-tetramethyl-[1,3,2]dioxaborolan-2-yl)-1H-pyrazole (0.15 g, 0.68 mmol) in THF (5 mL) was treated with NaH (0.032 g, 60% dispersion in oil, 0.81 mmol) at r.t. After 5 minutes [2-(chloromethoxy)ethyl]-trimethylsilane (0.14 mL, 0.81 mmol) was added and the reaction mixture stirred for 1.5 h. The reaction mixture was quenched with water (5 mL), diluted with EtOAc (20 mL) and the organic fraction separated. The organic fraction was dried (MgSO4), filtered and concentrated in vacuo. Purification by column chromatography (SiO2, 0-40% EtOAc/hexanes) gave the title compound (0.206 g, 86%) as a clear oil. δH (CDCl3) 5.35 (2H, s), 3.60 (2H, m), 2.50 (3H, s), 2.35 (3H, s), 1.35 (12H, s), 0.90 (2H, m), 0.00 (9H, s). LCMS (ES+) 353.0 (M+H)+.

Provenance & Evidence