Triisopropyl borate → {4-[4-(Trifluoromethoxy)phenoxy]phenyl}boronic acid

HRID 1908994Notes

Reaction equation

Br[C:2]1[CH:7]=[CH:6][C:5]([O:8][C:9]2[CH:14]=[CH:13][C:12]([O:15][C:16]([F:19])([F:18])[F:17])=[CH:11][CH:10]=2)=[CH:4][CH:3]=1.C([Li])CCC.C([O:28][B:29](OC(C)C)[O:30]C(C)C)(C)C>C1COCC1>[F:17][C:16]([F:19])([F:18])[O:15][C:12]1[CH:13]=[CH:14][C:9]([O:8][C:5]2[CH:6]=[CH:7][C:2]([B:29]([OH:30])[OH:28])=[CH:3][CH:4]=2)=[CH:10][CH:11]=1

Participants

Conditions

Temperature: -78 °C

Procedure

To a solution of 1-bromo-4-(4-(trifluoromethoxy)phenoxy)benzene (5.07 g, 15.2 mmol) in THF (76 ml) at −78° C. was added n-butyl lithium (7.6 ml, 2.5 M in hexanes, 19.0 mmol) dropwise. The reaction mixture was stirred 0.5 hours at −78° C., and triisopropylborate (7.0 ml, 30.4 mmol) was added. The reaction was stirred 4 hours at room temperature, quenched with 1 N HCl and stirred 0.5 hours at 0° C. The aqueous layer was extracted with ethyl acetate. The combined organic layers were extracted with brine and dried over magnesium sulfate. Purification by silica gel chromatography (0-10% methanol in dichloromethane) provided 4.38 g (4-(4-(trifluoromethoxy)phenoxy)phenyl)boronic acid (97% yield) as a light brown viscous oil. 1H NMR (400 MHz, CDCl3) δ 8.20 (d, J=8.9 Hz, 1H), 7.26 (d, J=8.9 Hz, 1H), 7.07-7.14 (m, 2H).

Workup

stirringThe reaction was stirred 4 hours at room temperature
customquenched with 1 N HCl
stirringstirred 0.5 hours at 0° C
extractionThe aqueous layer was extracted with ethyl acetate
extractionThe combined organic layers were extracted with brine
dry with materialdried over magnesium sulfate
customPurification by silica gel chromatography (0-10% methanol in dichloromethane)

Sources & evidence

ORD record: ord-b2dc143a055047e7b3c31648f31312a4
Source dataset: uspto-grants-2013_12
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US08598354B2

Reaction notes

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