1,3,5-Tribromobenzene → 1,3-Dibromo-5-dimesitylborylbenzene

HRID 1106389Notes

Reaction equation

C([Li])CCC.Br[C:7]1[CH:12]=[C:11]([Br:13])[CH:10]=[C:9]([Br:14])[CH:8]=1.[C:15]1([CH3:34])[CH:20]=[C:19]([CH3:21])[CH:18]=[C:17]([CH3:22])[C:16]=1[B:23]([C:25]1[C:30]([CH3:31])=[CH:29][C:28]([CH3:32])=[CH:27][C:26]=1[CH3:33])F>CCCCCC.C(OCC)C>[Br:13][C:11]1[CH:12]=[C:7]([B:23]([C:25]2[C:26]([CH3:33])=[CH:27][C:28]([CH3:32])=[CH:29][C:30]=2[CH3:31])[C:16]2[C:17]([CH3:22])=[CH:18][C:19]([CH3:21])=[CH:20][C:15]=2[CH3:34])[CH:8]=[C:9]([Br:14])[CH:10]=1

Participants

Conditions

Temperature: -78 °C

Procedure

6.25 ml (0.01 mol) of 1.6 M butyllithium in hexane are added over 5 minutes at -78° C. to a suspension of 3.14 g (0.01 mol) of 1,3,5-tribromobenzene in 50 ml of diethyl ether. The reaction mixture is stirred at -78° C. for 2 hours, during which a yellow-orange suspension is produced. 2.68 g (0.01 mol) of solid dimesitylfluoroborane are added, and the reaction mixture is warmed to room temperature over about one hour. The mixture is then diluted with 50 ml of hexane and cooled to 0° C. The solid produced is filtered, washed several times with cold hexane and then washed with water and, finally, with methanol, until the solid is colourless. Drying gives 3.54 g (0.0073 mol; i.e. 73% of theory) of a white solid (1,3-dibromo-5-dimesitylborylbenzene). Following purification by chromatography (hexane; SiO2) a melting point of 190-191° C. is obtained. Elemental analysis for C24H25BBr2 gives: C calc.: 59.55%; found: 59.52% H calc.: 5.21%; found: 5,12%

Workup

customis produced
temperaturethe reaction mixture is warmed to room temperature over about one hour
temperaturecooled to 0° C
customThe solid produced
filtrationis filtered
washwashed several times with cold hexane
washwashed with water
customDrying

Sources & evidence

ORD record: ord-6cdf08e273dc4f4ab05442fc9db2968a
Source dataset: uspto-grants-2000_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US06057078

Reaction notes

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