Reaction #2348085

Reaction equation

trimethyl borate

hydrochloric acid

THF

sec-butyl lithium

→

phenylboronic acid

Solvents

ethyl acetate

Conditions

Workup

1. 1
   workup.WAITthe stirring was continued for additional 180 minutes
2. 2
   OtherThe resulting reaction mixture
3. 3
   Otherto come to 0° C.
4. 4
   workup.ADDITIONpoured into a vessel
5. 5
   Temperaturehad been chilled at 0° C.
6. 6
   workup.ADDITIONmixed
7. 7
   Otherto be separated into an organic layer
8. 8
   ExtractionExtraction
9. 9
   WashThe extracts were washed with brine
10. 10
    Dryingdried over anhydrous magnesium sulfate
11. 11
    workup.DISTILLATIONThen, the solvent was distilled off under reduced pressure

Procedure

The compound (T17) and THF (1,000 ml) were put into a reaction vessel under an atmosphere of nitrogen, and chilled to −71° C. Then, a sec-butyl lithium solution (1.0 M in cyclohexane and n-hexane; 1,000 ml) were added dropwise thereto in the temperature range of −71° C. to −62° C., and the stirring was continued for additional 120 minutes. Subsequently, trimethyl borate (127.6 g) was added dropwise in the temperature range of −70° C. to −59° C., and the stirring was continued for additional 180 minutes. The resulting reaction mixture was allowed to come to 0° C., and then poured into a vessel containing 1N-hydrochloric acid (3,000 ml) and ethyl acetate (3,000 ml) which had been chilled at 0° C. and mixed. The mixture was then allowed to stand to be separated into an organic layer and an aqueous layer. Extraction was carried out and the resulting organic layer was fractionated. The extracts were washed with brine, and dried over anhydrous magnesium sulfate. Then, the solvent was distilled off under reduced pressure, whereby 115.9 g of phenylboronic acid derivative (T18) was obtained.

Source