Trimethyl borate → (2,3,5,6-Tetramethylphenyl)boronic acid

HRID 552874Notes

Reaction equation

HRID 552874 reaction equation
Br[C:2]1[C:8]([CH3:9])=[C:7]([CH3:10])[CH:6]=[C:4]([CH3:5])[C:3]=1[CH3:11].C([Li])CCC.[B:17](OC)([O:20]C)[O:18]C.C1([Li])C(C)=C(C)C=C(C)C=1C>C1COCC1.CCOCC>[C:2]1([B:17]([OH:20])[OH:18])[C:8]([CH3:9])=[C:7]([CH3:10])[CH:6]=[C:4]([CH3:5])[C:3]=1[CH3:11]

Participants

7

Reactant 4

HCID 8470Trimethyl borateHCID 742403-Bromo-1,2,4,5-tetramethylbenzeneHCID 178418339Butyllithium2×HCID 178506709HCID 178506709, compound

Product 1

HCID 16213799(2,3,5,6-Tetramethylphenyl)boronic acid

Reagents, catalysts & solvents 2

HCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-78 °C

Procedure

0.2 mol of 3-bromodurene is reacted in 800 ml of absolute THF by means of 0.25 mol of butyllithium under inert conditions at −78° C. On completion of the BuLi addition, the reaction mixture is stirred at −78° C. for another 1 h and then allowed to thaw. A 2 l flask is then initially charged with 500 ml of absolute ether and 0.3 mol of trimethyl borate at −78° C. and the duryllithium prepared beforehand is added dropwise within a period of 30 min. The mixture is then allowed to thaw and the reaction mixture is stirred for another 12 h. Finally, the reaction mixture is poured onto 2 N HCl-ice mixture and hydrolyzed for 12 h, the organic phase is extracted and concentrated, and the residue is admixed with pentane to precipitate out the product. The product is filtered off with suction and dried under reduced pressure mp: 101-3° C.

Workup

  1. stirringis stirred for another 12 h
  2. extractionthe organic phase is extracted
  3. concentrationconcentrated
  4. customto precipitate out the product
  5. filtrationThe product is filtered off with suction
  6. customdried under reduced pressure mp: 101-3° C.

Sources & evidence

ORD record
ord-cd488d500ff34ca881c00a9591a4ed1d
Source dataset
uspto-grants-2011_05
Patent number
US07951874B2

Reaction notes

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