2,2-Dimethoxypropane → (6S,7S)-8-oxo-2,2-dimethyl-5-methylidene-7-(1-(R)-benzyloxycarbonyloxyethyl)-3-oxa-1-azabicyclo[4.2.0]octane

HRID 1196204Notes

Reaction equation

HRID 1196204 reaction equation
[OH:1][CH2:2][C:3]([C@H:5]1[NH:8][C:7](=[O:9])[C@@H:6]1[C@H:10]([O:12][C:13]([O:15][CH2:16][C:17]1[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=1)=[O:14])[CH3:11])=[CH2:4].CO[C:25](OC)([CH3:27])[CH3:26].B(F)(F)F.CCOCC>ClCCl>[O:9]=[C:7]1[N:8]2[C@H:5]([C:3](=[CH2:4])[CH2:2][O:1][C:25]2([CH3:27])[CH3:26])[C@H:6]1[C@H:10]([O:12][C:13]([O:15][CH2:16][C:17]1[CH:18]=[CH:19][CH:20]=[CH:21][CH:22]=1)=[O:14])[CH3:11]

Participants

5

Reactant 3

HCID 64952,2-DimethoxypropaneHCID 8000Boron trifluoride etherateHCID 15000240(3S,4S)-4-(1-hydroxymethylethenyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-2-azetidinone

Product 1

HCID 22843873(6S,7S)-8-oxo-2,2-dimethyl-5-methylidene-7-(1-(R)-benzyloxycarbonyloxyethyl)-3-oxa-1-azabicyclo[4.2.0]octane

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Procedure

A solution of (3S,4S)-4-(1-hydroxymethylethenyl)-3-(1-(R)-benzyloxycarbonyloxyethyl)-2-azetidinone (3.7 g) and 2,2-dimethoxypropane (1.45 g) in dry dichloromethane (26 ml) was treated with boron trifluoride-etherate (0.14 ml) at room temperature for 1.5 hours. The reaction mixture was washed successively with saturated sodium bicarbonate (15 and water (20 ml×2), 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 (6S,7S)-8-oxo-2,2-dimethyl-5-methylidene-7-(1-(R)-benzyloxycarbonyloxyethyl)-3-oxa-1-azabicyclo[4.2.0]octane.

Workup

  1. washThe reaction mixture was washed successively with saturated sodium bicarbonate (15 and water (20 ml×2)
  2. dry with materialdried over anhydrous sodium sulfate
  3. filtrationFiltration and concentration of the filtrate in vacuo
  4. customgave an oily residue, which
  5. customwas purified by silica gel chromatography

Sources & evidence

ORD record
ord-77f765386da447f8b8048fd551aa2463
Source dataset
uspto-grants-1992_05
Patent number
US05112966

Reaction notes

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