Iodine → (3-tert-Butylphenyl)boronic acid

To a solution of dry THF (10 mL) was added magnesium (1.25 g, 52 mmol), 3-t-butyl bromobenzene (2.0 g, 9.4 mmol) and a crystal of iodine. The reaction was first heated slightly until the reaction started and then removed. The remaining 3-t-butyl bromobenzene (8.0 g, 37.7 mmol) was added via an addition funnel until the spontaneous refluxing stopped. The reaction mixture was heated to reflux for 2 hours. The Grignard was transferred via a syringe into a cooled solution (−40° C.) of trimethyl borate dissolved in THF and added over a 10 minute period. The reaction mixture was warmed to room temperature overnight. Ethyl acetate and distilled water were added to the reaction mixture and the layers separated. The organics were washed with brine and dried over magnesium sulfate. The solvent was concentrated and the product purified by a silica gel column using 10% ethyl acetate and hexanes as the eluants to give 3-t-butylphenyl boronic acid (4.0 g, 46% yield) as a white solid. The product was confirmed by GCMS and was used directly in the next step.

1. temperatureThe reaction was first heated slightly until the reaction
2. customremoved
3. temperaturespontaneous refluxing
4. temperatureThe reaction mixture was heated
5. temperatureto reflux for 2 hours
6. additionadded over a 10 minute period
7. distillationEthyl acetate and distilled water
8. additionwere added to the reaction mixture
9. customthe layers separated
10. washThe organics were washed with brine
11. dry with materialdried over magnesium sulfate
12. concentrationThe solvent was concentrated
13. customthe product purified by a silica gel column

ORD record

ord-f9ac140d50c94f1c850bb1ba99e2dd7d

Source dataset

uspto-grants-2011_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07915415B2