Boron tribromide → HCID 72195241, compound

HRID 626299Notes

Reaction equation

HRID 626299 reaction equation
C([O:8][C@@H:9]([C:11]1[O:12][C:13]2[C:18]([C:19](=[O:28])[C:20]=1[C:21]1[CH:26]=[CH:25][CH:24]=[C:23]([F:27])[CH:22]=1)=[CH:17][CH:16]=[CH:15][CH:14]=2)[CH3:10])C1C=CC=CC=1.B(Br)(Br)Br>ClCCl>[F:27][C:23]1[CH:22]=[C:21]([C:20]2[C:19](=[O:28])[C:18]3[C:13](=[CH:14][CH:15]=[CH:16][CH:17]=3)[O:12][C:11]=2[C@H:9]([OH:8])[CH3:10])[CH:26]=[CH:25][CH:24]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 117867654HCID 117867654, compound

Product 1

HCID 72195241HCID 72195241, compoundYield 80.4%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To (R)-2-(1-(benzyloxy)ethyl)-3-(3-fluorophenyl)-4H-chromen-4-one (5.0 g, 13.35 mmol) in dichloromethane (50 ml) cooled to −78° C., boron tribromide (1M in dichloromethane, 36.5 ml, 0.145 mmol) was added dropwise and stirred for 1 h. The reaction mixture was quenched with 2N HCl solution, extracted with dichloromethane, dried over sodium sulphate and concentrated under reduced pressure. The crude product was purified by column chromatography with ethyl acetate:petroleum ether to afford (R)-3-(3-fluorophenyl)-2-(1-hydroxyethyl)-4H-chromen-4-one as an off-white solid (3.05 g, 80%). 1H-NMR (6 ppm, CDCl3, 400 MHz): 8.24 (dd, J=7.9, 1.5 Hz, 1H), 7.73 (m, 1H), 7.54 (d, J=8.1 Hz, 1H), 7.44 (m, 2H), 7.13-7.01 (m, 3H), 4.71 (q, J=6.6 Hz, 1H), 1.56 (d, J=6.5 Hz, 3H). Mass: 284.9 (M+). Purity: 99.73%. [α]25D −0.605 (c=1, CHCl3). Enantiomeric excess: 95.2%, enriched in the late eluting isomer (retention time: 10.19 min.) as determined by HPLC on a chiralpak AD-H column.

Workup

  1. customThe reaction mixture was quenched with 2N HCl solution
  2. extractionextracted with dichloromethane
  3. dry with materialdried over sodium sulphate
  4. concentrationconcentrated under reduced pressure
  5. customThe crude product was purified by column chromatography with ethyl acetate

Sources & evidence

ORD record
ord-fe006469b450455c8e722b7815f7c87f
Source dataset
uspto-grants-2016_04
Patent number
US09309216B2

Reaction notes

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