Trimethylsilyl triflate → (3S,4R)-4-[(E)-4-{(2S)-1-allyloxycarbonylpyrrolidin-2-yl}-3-methyl-2-oxo-3-butenyl]-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-2-oxoazetidine

HRID 1650266Notes

Reaction equation

HRID 1650266 reaction equation
[CH2:1]([O:4][C:5]([N:7]1[CH2:11][CH2:10][CH2:9][C@H:8]1[CH:12]=[C:13]([CH3:17])[C:14](=[O:16])[CH3:15])=[O:6])[CH:2]=[CH2:3].FC(F)(F)S(O[Si](C)(C)C)(=O)=O.C(O[C@H:34]1[NH:37][C:36](=[O:38])[C@@H:35]1[C@H:39]([O:41][Si:42]([C:45]([CH3:48])([CH3:47])[CH3:46])([CH3:44])[CH3:43])[CH3:40])(=O)C.C(=O)([O-])O.[Na+]>ClCCl.C(OCC)(=O)C.[Br-].[Zn+2].[Br-].O.C(N(CC)CC)C>[CH2:1]([O:4][C:5]([N:7]1[CH2:11][CH2:10][CH2:9][C@H:8]1/[CH:12]=[C:13](\[CH3:17])/[C:14](=[O:16])[CH2:15][C@H:34]1[NH:37][C:36](=[O:38])[C@@H:35]1[C@H:39]([O:41][Si:42]([C:45]([CH3:46])([CH3:48])[CH3:47])([CH3:44])[CH3:43])[CH3:40])=[O:6])[CH:2]=[CH2:3]

Participants

10

Reactant 4

HCID 65367Trimethylsilyl triflateHCID 516892Sodium BicarbonateHCID 10935078AzetidonHCID 57093083(2S)-1-allyloxycarbonyl-2-(2-methyl-3-oxo-1-butenyl)pyrrolidine

Product 1

HCID 67792611(3S,4R)-4-[(E)-4-{(2S)-1-allyloxycarbonylpyrrolidin-2-yl}-3-methyl-2-oxo-3-butenyl]-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-2-oxoazetidineYield 56.5%

Reagents, catalysts & solvents 5

HCID 10421208Zinc bromideCatalystHCID 962WaterSolventHCID 6344DichloromethaneSolventHCID 8471TriethylamineSolventHCID 8857Ethyl AcetateSolvent2×

Conditions

Temperature
0 °C

Procedure

To a solution of (2S)-1-allyloxycarbonyl-2-(2-methyl-3-oxo-1-butenyl)pyrrolidine (9.00 g) and triethylamine (6.3 ml) in dichloromethane (200 ml) was added trimethylsilyl trifluoromethanesulfonate (11.7 ml) at -20° C. After stirring at 0° C. for 1 hour, a solution of (3R,4R)-4-acetoxy-3-[(1R)-1-t-butyldimethylsilyloxyethyl]-2-azetidinone (10.9 g) and zinc bromide (11.9 g) in ethyl acetate (70 ml) was added to the mixture and the resultant mixture was stirred at 0° C. for 45 minutes. The reaction mixture was taken up into a mixture of ethyl acetate (600 ml) and water (600 ml). After adjusting pH to 4 with aqueous sodium hydrogen carbonate, the organic layer was separated, washed with brine, dried over magnesium sulfate and evaporated. The residue was chromatographed on silica gel (400 ml) eluting with a mixture of n-hexane and ethyl acetate (9:1-5:5 V/V) to give (3S, 4R)-4-[(E)-4-{(2S)-1-allyloxycarbonylpyrrolidin-2-yl}-3-methyl-2-oxo-3-butenyl]-3[(1R)-1-t-butyldimethylsilyloxyethyl]-2-oxoazetidine (9.96 g).

Workup

  1. customthe organic layer was separated
  2. washwashed with brine
  3. dry with materialdried over magnesium sulfate
  4. customevaporated
  5. customThe residue was chromatographed on silica gel (400 ml)
  6. washeluting with a mixture of n-hexane and ethyl acetate (9:1-5:5 V/V)

Sources & evidence

ORD record
ord-8f81568565424a61bf1b2b9db9367f35
Source dataset
uspto-grants-1990_05
Patent number
US04923857

Reaction notes

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