N-Methoxy-N-methyl-(2S)-(3,4-dichlorophenyl)-4-pentenamide → 3-(S)-(3,4-dichlorophenyl)-5-hexen-2-one

HRID 1737436Notes

Reaction equation

HRID 1737436 reaction equation
CON(C)[C:4](=[O:17])[C@H:5]([C:9]1[CH:14]=[CH:13][C:12]([Cl:15])=[C:11]([Cl:16])[CH:10]=1)[CH2:6][CH:7]=[CH2:8].[CH3:19][Li]>O1CCCC1>[Cl:16][C:11]1[CH:10]=[C:9]([C@H:5]([CH2:6][CH:7]=[CH2:8])[C:4](=[O:17])[CH3:19])[CH:14]=[CH:13][C:12]=1[Cl:15]

Participants

4

Reactant 2

HCID 18392767N-Methoxy-N-methyl-(2S)-(3,4-dichlorophenyl)-4-pentenamideHCID 178418348HCID 178418348, compound

Product 1

HCID 183927553-(S)-(3,4-dichlorophenyl)-5-hexen-2-oneYield 93%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Procedure

A solution of 319 mg (1.11 mmoL) of N-methoxy-N-methyl-2-(S)-(3,4-dichlorophenyl)-4-pentenamide (from Step 1 above) in 10 mL of dry tetrahydrofuran was cooled to -70° C. and treated with 1.0 mL (1.40 mmol) of methyllithium and stirred between -70° C to -40° C. After 3 hours, the reaction was quenched with 5 mL of water, and diluted with 10 mL of ethyl acetate. The layers were separated and the organic layer was washed with water (3×10 mL). The aqueous layers were extracted with 10 mL of ethyl acetate. The combined organic layers were washed with 10 mL of saturated aqueous sodium chloride solution, dried over anhydrous sodium sulfate, filtered, and concentrated in vacuo. Flash chromatography on 44 g of silica gel using 1:3 v/v ethyl acetate/hexane as the eluant afforded 250 mg (93%) of the title compound as a clear oil. 1H NMR (400 MHz, CDCl3) δ 2.07 (s, 3H), 2.36 (pentet, 1H), 2.72 (pentet, 1H), 3.64 (t, 1H), 4.95-5.01 (m, 2H), 5.55-5.65 (m, 1H), 7.03 (dd, 1H), 7.30 (d, 1H), 7.39 (d, 1H).

Workup

  1. customthe reaction was quenched with 5 mL of water
  2. additiondiluted with 10 mL of ethyl acetate
  3. customThe layers were separated
  4. washthe organic layer was washed with water (3×10 mL)
  5. extractionThe aqueous layers were extracted with 10 mL of ethyl acetate
  6. washThe combined organic layers were washed with 10 mL of saturated aqueous sodium chloride solution
  7. dry with materialdried over anhydrous sodium sulfate
  8. filtrationfiltered
  9. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-8767999d5fd24d95890c6725a82093ef
Source dataset
uspto-grants-1999_10
Patent number
US05962462

Reaction notes

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