Benzyl 3-oxoazetidine-1-carboxylate → Benzyl 3-methyleneazetidine-1-carboxylate

HRID 605672Notes

Reaction equation

HRID 605672 reaction equation
[CH3:1][C:2]([CH3:5])([O-])[CH3:3].[K+].O=C1C[N:10]([C:12]([O:14][CH2:15][C:16]2[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=2)=[O:13])C1>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C(OCC)C>[CH2:1]=[C:2]1[CH2:5][N:10]([C:12]([O:14][CH2:15][C:16]2[CH:21]=[CH:20][CH:19]=[CH:18][CH:17]=2)=[O:13])[CH2:3]1

Participants

5

Reactant 2

HCID 10632047Benzyl 3-oxoazetidine-1-carboxylateHCID 23665647Potassium tert-butoxide

Product 1

HCID 67051849Benzyl 3-methyleneazetidine-1-carboxylateYield 75%

Reagents, catalysts & solvents 2

HCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 3283Diethyl EtherSolvent2×

Procedure

A suspension of methyltriphenylphosphonium bromide (23.0 g, 0.0649 mol) and potassium tert-butoxide (7.3 g, 0.0649 mol) in diethyl ether (140 mL) was stirred at room temperature for 20 min, and then heated to 35° C. for 1 h. To this bright yellow reaction mixture was slowly added a dilute solution of phenylmethyl 3-oxoazetidine-1-carboxylate (3.33 g, 0.0162 mol) in diethyl ether (50 mL) The reaction mixture was stirred at 35° C. for 12 hours then filtered through a bed of celite and rinsed with ethyl ether. The filtrate was washed with water and brine, dried over anhydrous magnesium sulfate and concentrated. The residue was purified by flash chromatography (SiO2, 5-10% ethyl acetate in hexanes) to afford phenylmethyl 3-methylideneazetidine-1-carboxylate (2.46 g, 75% yield) as a clear and colorless oil). 1H NMR (400 MHz, CDCl3): 7.27-7.22 (m, 5H), 5.02 (s, 2H), 4.93-4.90 (m, 2H), 4.48-4.47 (m, 4H). MS (EI) for C12H13NO2: 203 (M+).

Workup

  1. temperatureheated to 35° C. for 1 h
  2. stirringwas stirred at 35° C. for 12 hours
  3. filtrationthen filtered through a bed of celite and
  4. washrinsed with ethyl ether
  5. washThe filtrate was washed with water and brine
  6. dry with materialdried over anhydrous magnesium sulfate
  7. concentrationconcentrated
  8. customThe residue was purified by flash chromatography (SiO2, 5-10% ethyl acetate in hexanes)

Sources & evidence

ORD record
ord-7092208bcf494bafa4f7228949258667
Source dataset
uspto-grants-2011_03
Patent number
US07915250B2

Reaction notes

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