tert-Butyl carbamate → tert-Butyl (2E)-but-2-enoylcarbamate

HRID 1767267Notes

Reaction equation

HRID 1767267 reaction equation
[C:1](=[O:8])([O:3][C:4]([CH3:7])([CH3:6])[CH3:5])[NH2:2].[Li]CCCC.[C:14](Cl)(=[O:18])[CH:15]=[CH:16][CH3:17].[Li]CCCC.C(Cl)(=O)C=CC.C([O-])(O)=O.[Na+]>C1COCC1>[C:14]([NH:2][C:1](=[O:8])[O:3][C:4]([CH3:7])([CH3:6])[CH3:5])(=[O:18])/[CH:15]=[CH:16]/[CH3:17]

Participants

7

Reactant 5

HCID 77922tert-Butyl carbamateHCID 790802-Butenoyl chlorideHCID 516892Sodium BicarbonateHCID 178418339ButyllithiumHCID 178450590HCID 178450590, compound

Product 1

HCID 11298363tert-Butyl (2E)-but-2-enoylcarbamateYield 81%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

To a solution of tert-butyl carbamate (1.0 g, 8.54 mmol) in THF (20 mL) at −78° C., were added nBuLi and 2-butenoyl chloride successively, in the following quantities (nBuLi/2-butenoyl chloride): 5.34/0.41, 2.67/0.21, 1.34/0.10, 0.67/0.05, 0.34/0.03 mL. Stirring was continued for 30 min, before the reaction mixture was poured into an ice-cooled solution of saturated aq. NaHCO3 (50 mL) and extracted with EtOAc. The combined organic layers were washed with brine, dried over MgSO4, and evaporated. The crude product was purified by flash chromatography (Et2O:pet. ether, 1:3, Rf 0.4) to give the product as a white solid. Yield 81% (1.28 g). m.pt. 138–139° C. 1H NMR: δ 1.49 (s, 9H, tBu); 1.92 (dd, 1H, CH3CH, 2JHH=6.8 Hz, 3JHH=1.5 Hz); 6.82 (dd, 1H, COCH, 2JHH=15.2 Hz, 3JHH=1.5 Hz); 7.05–7.15 (m, 1H, CH3CH); 7.31 (s, br, 1H, NH). 13C NMR: δ 15.9 (CH3CH), 27.9 (C(CH3)3), 82.3 (C(CH3)3), 121.2 (COCH), 145.5 (CH3CH), 150.5(CO2), 166.3 (COCH). m/z (HR-ESMS): Expected 185.1052 (M+), observed 185.1046. Anal. calcd for C9H15NO3: C, 58.36; H, 8.16; N, 7.56%. Found: C, 58.08; H, 8.05; N, 7.63%.

Workup

  1. extractionextracted with EtOAc
  2. washThe combined organic layers were washed with brine
  3. dry with materialdried over MgSO4
  4. customevaporated
  5. customThe crude product was purified by flash chromatography (Et2O:pet. ether, 1:3, Rf 0.4)

Sources & evidence

ORD record
ord-139b627578ac47139154177196b87f89
Source dataset
uspto-grants-2007_06
Patent number
US07232923B2

Reaction notes

Loading…