2-Methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane → 1-[2-(oxan-2-yloxy)ethyl]-4-(tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

Participants

Reaction Conditions

Reaction Steps

A solution of iPrMgCl (2M in THF, 68.3 mL, 136.6 mmol) was added drop wise to a solution of 4-iodo-1-[2-(tetrahydro-pyran-2-yloxy)-ethyl]-1H-pyrazole (22 g, 68.3 mmol) in anhydrous THF (200 mL) 0° C. The reaction was stirred for 1 hour at 0° C. under nitrogen. 2-Methoxy-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (16.1 g, 0.101 mol) was added and the resulting yellow solution was allowed to stir for 1 hour at ambient temperature under nitrogen. The reaction was quenched with sat. aqueous solution of NH4Cl and was diluted with EtOAc. The organic layer was washed with brine, and dried over Na2SO4, concentrated under reduced pressure, and purified by silica gel chromatography to give 1-(2-((tetrahydro-2H-pyran-2-yl)oxy)ethyl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole as a oil. 1H-NMR (400 MHz, CDCl3): δ 7.75 (m, 2H), 4.48 (s, 1H), 4.30 (m, 2H), 4.10 (m, 1H), 3.78-3.71 (m, 1H), 3.63-3.59 (m, 1H), 3.42-3.38 (m, 1H), 1.60-1.46 (m, 6H), 1.29 (s, 12H).

Provenance & Evidence