Potassium Carbonate → Methyl 4-ethenyl-1H-pyrrole-2-carboxylate

HRID 1877782Notes

Reaction equation

HRID 1877782 reaction equation
Br[C:2]1[CH:3]=[C:4]([C:7]([O:9][CH3:10])=[O:8])[NH:5][CH:6]=1.N1C=CC=[CH:13][CH:12]=1.C(B1OB(C=C)OB(C=C)O1)=C.C(=O)([O-])[O-].[K+].[K+]>O1CCOCC1.O.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.[Pd].[Pd].C(P(C(C)(C)C)[C-]1C=CC=C1)(C)(C)C.[C-]1(P(C(C)(C)C)C(C)(C)C)C=CC=C1.[Fe+2]>[CH:12]([C:2]1[CH:3]=[C:4]([C:7]([O:9][CH3:10])=[O:8])[NH:5][CH:6]=1)=[CH2:13]

Participants

8

Reactant 3

HCID 11430Potassium CarbonateHCID 27348062,4,6-Trivinylboroxin-Pyridine ComplexHCID 2763594Methyl 4-bromo-1H-pyrrole-2-carboxylate

Product 1

HCID 18784613Methyl 4-ethenyl-1H-pyrrole-2-carboxylateYield 101.3%

Reagents, catalysts & solvents 4

HCID 9811564Bis(dibenzylideneacetone)palladiumCatalystHCID 12976736Bis(ditert-butyl(cyclopenta-2,4-dien-1-yl)phosphane);iron(2+)CatalystHCID 962WaterSolventHCID 312751,4-DioxaneSolvent

Procedure

Degas, by purging with nitrogen for 10 minutes, a solution of methyl 4-bromo-1H-pyrrole-2-carboxylate (2.0 g, 9.8 mmoles), triethenylboroxin pyridine (1.3 equiv; 3.1 g, 12.7 mmoles), and potassium carbonate (3 equiv; 4.1 g, 29.4 mmoles) in a mixture of 1,4-dioxane (20 mL) and water (10 mL). Add tris(dibenzylideneacetonyl)bis-palladium (Pd2(dba)3) (0.01 equiv; 0.0925 g, 98.0 μmoles) and 1,1′-bis(di-tert-butylphosphino)ferrocene (dtbpf) (0.03 equiv; 0.0853 g, 294.1 μmoles) and heat at 95° C. for 3 h. Cool to room temperature then partition between water (50 mL) and a 1:1 mixture of hexanes/diethyl ether (100 mL). The organic layer is washed with water (2×50 mL) then brine. Dry over Na2SO4, filter and evaporate to give methyl 4-ethenyl-1H-pyrrole-2-carboxylate as a straw colored oil (1.5 g). Use without further purification. 1H-NMR (CDCl3), δ: 8.90 (1H, br. s), 7.02 (1H, m), 6.95 (1H, m), 6.56 (1H, q) 5.48 (1H, dd), 5.05 (1H, dd), 3.86 (3H, s).

Workup

  1. customDegas
  2. customby purging with nitrogen for 10 minutes
  3. customthen partition between water (50 mL)
  4. additiona 1:1 mixture of hexanes/diethyl ether (100 mL)
  5. washThe organic layer is washed with water (2×50 mL)
  6. dry with materialDry over Na2SO4
  7. filtrationfilter
  8. customevaporate

Sources & evidence

ORD record
ord-b9f1141a39304a8dae5b27117d501741
Source dataset
uspto-grants-2012_11
Patent number
US08314092B2

Reaction notes

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