Methanol → (R)-2-Bromo-1-(2,2-dimethyl4H-benzo[1,3]dioxin-6-yl)ethanol

HRID 2118299Notes

Reaction equation

HRID 2118299 reaction equation
B.C1COCC1.[Br:7][CH2:8][C:9]([C:11]1[CH:22]=[CH:21][C:14]2[O:15][C:16]([CH3:20])([CH3:19])[O:17][CH2:18][C:13]=2[CH:12]=1)=[O:10].CO>C1COCC1>[Br:7][CH2:8][C@@H:9]([C:11]1[CH:22]=[CH:21][C:14]2[O:15][C:16]([CH3:19])([CH3:20])[O:17][CH2:18][C:13]=2[CH:12]=1)[OH:10]

Participants

5

Reactant 3

HCID 887MethanolHCID 2723981Borane;tetrahydrofuranHCID 11150315Ethanone, 2-bromo-1-(2,2-dimethyl-4H-1,3-benzodioxin-6-yl)-

Product 1

HCID 25098927(R)-2-Bromo-1-(2,2-dimethyl4H-benzo[1,3]dioxin-6-yl)ethanolYield 84.3%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

A solution R-diphenylprolinol (75 mg) in THF (2 ml) was treated with borane-THF (1M, 20.5 ml) over 20 min at 20° C. under nitrogen. After the addition was complete the solution was kept between 30 and 35° C. for 1 h and then cooled in ice and 2-bromo-1-(2,2-dimethyl-4H-1,3-benzodioxin-6-yl)ethanone (DE3513885) (3.9 g) in THF (10 ml) was added over 1.5 h keeping the temperature below 5° C. The mixture was stirred under nitrogen for a further 0.5 h and then methanol (4 ml) was added at 0° C. The solvent was removed under reduced pressure and the residue was purified by chromatography on flash silica gel eluting with ethyl acetate-cyclohexane (1:4) to give the title compound (3.31 g) δ (CDCl3) 7.15 (1H, dd, J 8, 2 Hz), 7.03 (1H, br s), 6.82 (1H, d, J 8 Hz), 4.85 (3H, s and m), 3.61 (1H, dd, J 10, 4 Hz), 3.50 (1H, 9 Hz), 1.54 (6H, s).

Workup

  1. additionAfter the addition
  2. temperaturecooled in ice
  3. customthe temperature below 5° C
  4. customThe solvent was removed under reduced pressure
  5. customthe residue was purified by chromatography on flash silica gel eluting with ethyl acetate-cyclohexane (1:4)

Sources & evidence

ORD record
ord-2cb726b50fc744eab72a285c454b940e
Source dataset
uspto-grants-2008_10
Patent number
US07442837B2

Reaction notes

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