Boron trifluoride etherate → (3S,4S)-4-(1-(R)-hydroxymethylethyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-2-azetidinone

HRID 1196213Notes

Reaction equation

HRID 1196213 reaction equation
[Si]([O:8][CH2:9][C@@H:10]([C@H:12]1[N:15](C(CC2C=CC(OC)=CC=2)CC2C=CC(OC)=CC=2)[C:14](=[O:35])[C@@H:13]1[C@H:36]([O:38][C:39]([O:41][CH2:42][C:43]1[CH:48]=[CH:47][CH:46]=[CH:45][CH:44]=1)=[O:40])[CH3:37])[CH3:11])(C(C)(C)C)(C)C.COC1C=CC=C(OC)C=1.B(F)(F)F.CCOCC>ClCCl>[OH:8][CH2:9][C@@H:10]([C@@H:12]1[NH:15][C:14](=[O:35])[C@@H:13]1[C@H:36]([O:38][C:39]([O:41][CH2:42][C:43]1[CH:44]=[CH:45][CH:46]=[CH:47][CH:48]=1)=[O:40])[CH3:37])[CH3:11]

Participants

5

Reactant 3

HCID 8000Boron trifluoride etherateHCID 90251,3-DimethoxybenzeneHCID 67798445(3S,4R)-4-(1-(R)-t-butyldimethylsilyloxymethylethyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-1-di(p-anisyl)methyl-2-azetidinone

Product 1

HCID 13960427(3S,4S)-4-(1-(R)-hydroxymethylethyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-2-azetidinone

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

To a solution of (3S,4R)-4-(1-(R)-t-butyldimethylsilyloxymethylethyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-1-di(p-anisyl)methyl-2-azetidinone (20 g) in dry dichloromethane (200 ml) were added 1,3-dimethoxybenzene (7.8 g) and boron trifluoride etherate (23 g) at 10 °-20° C., and the resultant mixture was stirred at room temperature for 3 hours, followed by heating under reflux for 3-5 hours. The reaction mixture was cooled down to 10°-15° C., washed successively with brine (200 ml×2), 2.5% sodium bicarbonate (200 ml) and brine (200 ml) and dried over anhydrous sodium sulfate. Filtration and concentration of the filtrate in vacuo gave an oily residue which was purified by silica gel chromatography to yield (3S,4S)-4-(1-(R)-hydroxymethylethyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-2-azetidinone.

Workup

  1. temperatureby heating
  2. temperatureunder reflux for 3-5 hours
  3. temperatureThe reaction mixture was cooled down to 10°-15° C.
  4. washwashed successively with brine (200 ml×2), 2.5% sodium bicarbonate (200 ml) and brine (200 ml)
  5. dry with materialdried over anhydrous sodium sulfate
  6. filtrationFiltration and concentration of the filtrate in vacuo
  7. customgave an oily residue which
  8. customwas purified by silica gel chromatography

Sources & evidence

ORD record
ord-ca7f59f82f7343c2823d7361a964354d
Source dataset
uspto-grants-1992_05
Patent number
US05112966

Reaction notes

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