Methyl iodide → 3-Cyano-2-methyl-5-trimethylsilylthiophene

HRID 1107727Notes

Reaction equation

HRID 1107727 reaction equation
C([Li])CCC.C(NC(C)C)(C)C.[C:13]([C:15]1[CH:19]=[CH:18][S:17][CH:16]=1)#[N:14].[CH3:20]I.[CH3:22][Si:23](Cl)([CH3:25])[CH3:24]>C1COCC1>[C:13]([C:15]1[CH:19]=[C:18]([Si:23]([CH3:25])([CH3:24])[CH3:22])[S:17][C:16]=1[CH3:20])#[N:14]

Participants

7

Reactant 5

HCID 6328Methyl iodideHCID 6397ChlorotrimethylsilaneHCID 7912DiisopropylamineHCID 74231Thiophene-3-carbonitrileHCID 178418339Butyllithium

Product 1

HCID 187859463-Cyano-2-methyl-5-trimethylsilylthiophene

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent3×

Conditions

Temperature
-78 °C

Procedure

n-Butyllithium (1.4 M in hexanes, 1.3 ml, 1.8 mmol) was added dropwise to a stirred solution of diisopropylamine (0.25 ml) in dry THF (16 ml) at -5-0° C. and the solution stirred for 30 min. The mixture was cooled to -78° C. and a solution of 3-cyanothiophene (0.20 g, 1.8 mmol) in THF (4 ml) added dropwise, followed by methyl iodide (0.23 ml, 0.35 g, 2.5 mmol) after min. The mixture was stirred for 20 min., warmed to room temperature over 30 min. and evaporated. Meanwhile n-butyllithium (1.4 M in hexanes, 1.31 ml) was added dropwise to a stirred solution of diisopropylamine (0.25 ml) in dry THF (16 ml) at -5-0° C. and the solution stirred for 30 min. The mixture was cooled to 78° C. and the crude 3-cyano-2-methylthiophene prepared above was added dropwise in THF (4 ml), followed by trimethylsilylchloride (0.43 ml) after 1 min. The mixture was stirred for 20 min., warmed to room temperature over 30 min. and evaporated to afford a yellow oil. Purification by flash chromatography on untreated neutral alumina, eluting with 5% diethyl ether in hexane, gave 3-cyano-2-methyl-5-trimethylsilylthiophene as a clear oil (0.20 g). M+ 195; 360 MHz 1H n.m.r (CDCl3) 7.19 (1H, s), 2.66 (3H, s), 0.31 (9H, s).

Workup

  1. stirringThe mixture was stirred for 20 min.
  2. temperaturewarmed to room temperature over 30 min.
  3. customevaporated
  4. additionMeanwhile n-butyllithium (1.4 M in hexanes, 1.31 ml) was added dropwise to a stirred solution of diisopropylamine (0.25 ml) in dry THF (16 ml) at -5-0° C.
  5. stirringthe solution stirred for 30 min
  6. temperatureThe mixture was cooled to 78° C.
  7. customthe crude 3-cyano-2-methylthiophene prepared
  8. stirringThe mixture was stirred for 20 min.
  9. temperaturewarmed to room temperature over 30 min.
  10. customevaporated
  11. customto afford a yellow oil
  12. customPurification by flash chromatography on untreated neutral alumina
  13. washeluting with 5% diethyl ether in hexane

Sources & evidence

ORD record
ord-dfe16d3415cb49f9bb8b22bbd1249548
Source dataset
uspto-grants-2000_05
Patent number
US06063789

Reaction notes

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