Boron tribromide → HCID 21079763, compound

HRID 457530Notes

Reaction equation

HRID 457530 reaction equation
[CH:1]([C:4]1[CH:9]=[CH:8][C:7]([CH2:10][C:11]([O:13][CH2:14][CH3:15])=[O:12])=[CH:6][C:5]=1[O:16]C)([CH3:3])[CH3:2].B(Br)(Br)Br>C(Cl)Cl>[OH:16][C:5]1[CH:6]=[C:7]([CH2:10][C:11]([O:13][CH2:14][CH3:15])=[O:12])[CH:8]=[CH:9][C:4]=1[CH:1]([CH3:3])[CH3:2]

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 21079764HCID 21079764, compound

Product 1

HCID 21079763HCID 21079763, compoundYield 94.4%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Conditions

Temperature
-78 °C

Procedure

A solution of 4h (3.38 g; 14.30 mmol) and CH2Cl2 (150 mL) were cooled to −78° C. and a solution of BBr3 (5.41 mL; 57.22 mmol) in 130 mL of CH2Cl2 were added dropwise over a 30 m period. The reaction mixture was stirred at −78° C. for 1 h, allowed to warm to rt for 4 h and re-cooled to −78° C. and carefully quenched with sat'd. NaHCO3 (80 mL). The aqueous layer was extracted with CH2Cl2 (1×100 mL), EtOAc (50 mL) and the combined aqueous layers washed with water and brine, dried (Na2SO4) and evaporated to yield a light brown oil. The phenol was purified by silica gel chromatography and eluted with CH2Cl2:hexane (3:1)→CH2Cl2→CH2Cl2:EtOAc (100:4) to yield ethyl 4-iso-propyl-3-hydroxyphenylacetate (5c; 3.0 g; 94%)

Workup

  1. temperatureto warm to rt for 4 h
  2. temperaturere-cooled to −78° C.
  3. customcarefully quenched with sat'd
  4. extractionThe aqueous layer was extracted with CH2Cl2 (1×100 mL), EtOAc (50 mL)
  5. washthe combined aqueous layers washed with water and brine
  6. dry with materialdried (Na2SO4)
  7. customevaporated
  8. customto yield a light brown oil
  9. customThe phenol was purified by silica gel chromatography
  10. washeluted with CH2Cl2:hexane (3:1)→CH2Cl2→CH2Cl2:EtOAc (100:4)

Sources & evidence

ORD record
ord-4969898bef694b3d95e7dccfebe59c61
Source dataset
uspto-grants-2007_03
Patent number
US07189718B2

Reaction notes

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