Ammonium Chloride → tert-Butyl 5-ethenyl-1H-indole-1-carboxylate

HRID 2361897Notes

Reaction equation

HRID 2361897 reaction equation
[Li][CH2:2]CCC.[C:6]([O:10][C:11]([N:13]1[C:21]2[C:16](=[CH:17][C:18]([CH:22]=O)=[CH:19][CH:20]=2)[CH:15]=[CH:14]1)=[O:12])([CH3:9])([CH3:8])[CH3:7].[Cl-].[NH4+]>[Br-].C[P+](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C1COCC1>[C:6]([O:10][C:11]([N:13]1[C:21]2[C:16](=[CH:17][C:18]([CH:22]=[CH2:2])=[CH:19][CH:20]=2)[CH:15]=[CH:14]1)=[O:12])([CH3:9])([CH3:8])[CH3:7]

Participants

6

Reactant 3

HCID 25517Ammonium ChlorideHCID 11172622tert-Butyl 5-formyl-1H-indole-1-carboxylateHCID 178418339Butyllithium

Product 1

HCID 66890900tert-Butyl 5-ethenyl-1H-indole-1-carboxylateYield 130.5%

Reagents, catalysts & solvents 2

HCID 74505Methyltriphenyliphosphonium bromideCatalystHCID 8028TetrahydrofuranSolvent2×

Procedure

To a suspension of methyltriphenylphosphonium bromide (8.1 g, 22.7 mmol) in THF (140 mL) at 0° C. was added nBuLi (1.6 M in hexanes, 14.2 mL, 22.7 mmol) dropwise over 10 min. After 20 min of stirring, a solution of the 5-formyl-indole-1-carboxylic acid tert-butyl ester (4.63 g, 14.8 mmol) in THF (20 mL) was introduced slowly over 20 min. The reaction was warmed slowly to room temperature, stirred 30 min. The reaction mixture was poured into saturated ammonium chloride and the separated aqueous phase was extracted with ethylacetate (3×100 mL). The combined organic phase was dried over sodium sulfate, filtered and concentrated. The residue was purified by chromatography (methylene chloride to 1% acetone-methylene chloride) to give 5-vinyl-indole-1-carboxylic acid tert-butyl ester (4.7 g, 100%) or similarly 6-vinyl-indole-1-carboxylic acid tert-butyl ester.

Workup

  1. stirringstirred 30 min
  2. extractionthe separated aqueous phase was extracted with ethylacetate (3×100 mL)
  3. dry with materialThe combined organic phase was dried over sodium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated
  6. customThe residue was purified by chromatography (methylene chloride to 1% acetone-methylene chloride)

Sources & evidence

ORD record
ord-fb23976d7add41a4bb4e5d0674425c72
Source dataset
uspto-grants-2014_04
Patent number
US08691814B2

Reaction notes

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