Hydrochloric Acid → 4-(2-(Tert-butyldimethylsilyloxy)ethyl)-3-ethylphenylboronic acid

HRID 735621Notes

Reaction equation

C([Li])CCC.Br[C:7]1[CH:22]=[CH:21][C:10]([CH2:11][CH2:12][O:13][Si:14]([C:17]([CH3:20])([CH3:19])[CH3:18])([CH3:16])[CH3:15])=[C:9]([CH2:23][CH3:24])[CH:8]=1.[B:25](OC)([O:28]C)[O:26]C.Cl>C1COCC1>[Si:14]([O:13][CH2:12][CH2:11][C:10]1[CH:21]=[CH:22][C:7]([B:25]([OH:28])[OH:26])=[CH:8][C:9]=1[CH2:23][CH3:24])([C:17]([CH3:20])([CH3:19])[CH3:18])([CH3:16])[CH3:15]

Participants

Conditions

Temperature: -78 °C

Procedure

n-Butyl Lithium (4.7 mL) was added to a solution of 46A (2.1 g, 6.1 mmol) in THF at −78° C. After stirring to 10 min at −78° C., trimethyl borate (1.0 mL, 12.3 mmol) was added dropwise. After warming to ambient temperature, the reaction mixture was stirred an additional 2 h. HCl (1.0 M, 30 mL, aqueous) was added to the mixture at −40° C. and stirred at −20° C. for 30 min. The solution was extracted with diethyl ether. The combined organics were washed with brine, dried over Na2SO4 and concentrated in vacuo. The resulting oil was purified by flash chromatography (0% to 20% MeOH in CH2Cl2) to yield 46B (0.90 mg, 48%) as a clear oil. MS (ESI) m/z 307.4 (M−H)−.

Workup

temperatureAfter warming to ambient temperature
stirringthe reaction mixture was stirred an additional 2 h
stirringstirred at −20° C. for 30 min
extractionThe solution was extracted with diethyl ether
washThe combined organics were washed with brine
dry with materialdried over Na2SO4
concentrationconcentrated in vacuo
customThe resulting oil was purified by flash chromatography (0% to 20% MeOH in CH2Cl2)

Sources & evidence

ORD record: ord-8c52d6f0875e4171a07e95e81c9f8dc8
Source dataset: uspto-grants-2009_09
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07592331B2

Reaction notes

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