Allyl bromide → 1-(Prop-2-en-1-yl)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-1H-pyrazole

HRID 417930Notes

Reaction equation

[NH:1]1[CH:5]=[C:4]([B:6]2[O:14][C:11]([CH3:13])([CH3:12])[C:8]([CH3:10])([CH3:9])[O:7]2)[CH:3]=[N:2]1.[CH2:15](Br)[CH:16]=[CH2:17].C[Si]([N-][Si](C)(C)C)(C)C.[Na+]>C1COCC1>[CH2:17]([N:2]1[CH:3]=[C:4]([B:6]2[O:7][C:8]([CH3:9])([CH3:10])[C:11]([CH3:13])([CH3:12])[O:14]2)[CH:5]=[N:1]1)[CH:16]=[CH2:15]

Participants

Conditions

Temperature: 70 °C

Procedure

A mixture of 4-pyrazoleboronic acid pinacol ester (3.0 g, 15.6 mmol), allyl bromide (6.9 g, 77 mmol) and sodium bis(trimethylsilyl)amide (20.5 mL of a 1.5N solution in THF, 30.7 mmol) in THF (20 mL) was heated to 70° C. overnight. After cooling to r.t. the reaction was quenched with water (15 mL) and extracted with EtOAc (2×30 mL). The combined organic fractions were washed with brine (50 mL), dried (MgSO4) and concentrated in vacuo to give the title compound (3.4 g, 94%) as a yellow oil. δH (CDCl3) 1.20 (12H, s), 4.61-4.67 (2H, m), 5.06-5.24 (2H, m), 5.79-6.01 (1H, m), 7.60 (1H, s), 7.69 (1H, s).

Workup

temperatureAfter cooling to r.t. the reaction
customwas quenched with water (15 mL)
extractionextracted with EtOAc (2×30 mL)
washThe combined organic fractions were washed with brine (50 mL)
dry with materialdried (MgSO4)
concentrationconcentrated in vacuo

Sources & evidence

ORD record: ord-7f1c803fe2e44e2fa4fc2fab3fa3f91a
Source dataset: uspto-grants-2012_01
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08093238B2

Reaction notes

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