((1,1-Dimethyl-2-propynyl)oxy)trimethylsilane → 2-Methoxy-5-(4-methyl-4-(trimethylsilyloxy)pent-2-ynoyl)benzonitrile

HRID 655451Notes

Reaction equation

HRID 655451 reaction equation
[CH3:1][Si:2]([CH3:10])([CH3:9])[O:3][C:4]([CH3:8])([C:6]#[CH:7])[CH3:5].[Li]CCCC.[C:16]([C:18]1[CH:19]=[C:20]([CH:27]=[CH:28][C:29]=1[O:30][CH3:31])[C:21](N(OC)C)=[O:22])#[N:17]>C1COCC1>[CH3:31][O:30][C:29]1[CH:28]=[CH:27][C:20]([C:21](=[O:22])[C:7]#[C:6][C:4]([CH3:8])([O:3][Si:2]([CH3:10])([CH3:9])[CH3:1])[CH3:5])=[CH:19][C:18]=1[C:16]#[N:17]

Participants

5

Reactant 3

HCID 87344((1,1-Dimethyl-2-propynyl)oxy)trimethylsilaneHCID 593547633-cyano-N,4-dimethoxy-N-methylbenzamideHCID 178418339Butyllithium

Product 1

HCID 593548212-Methoxy-5-(4-methyl-4-(trimethylsilyloxy)pent-2-ynoyl)benzonitrileYield 56%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Conditions

Temperature
-78 °C

Procedure

To a −78° C. stirred solution of trimethyl(2-methylbut-3-yn-2-yloxy)silane (1.9 g, 12.501 mmol) in dry THF (25 mL), n-BuLi (2.80 mL, 4.50 mmol, 1.6 M in hexane) was added dropwise over 10 minutes under an inert atmosphere. The reaction was stirred for 30 min at −78° C., and then a solution of 3-cyano-N,4-dimethoxy-N-methylbenzamide (1.10 g, 5.01 mmol) in dry THF (10 mL) was added to reaction mixture and stirring was continued for an additional 3 h at −78° C. The reaction mixture was quenched with a saturated NH4Cl solution and extracted with EtOAc (2×50 mL). The combined organic layers were washed with water (20 mL) and brine (20 mL), dried over Na2SO4, filtered and concentrated in vacuo to obtain the crude product. The crude material was purified via silica gel column chromatography eluting with 5% EtOAc in hexanes to afford 2-methoxy-5-(4-methyl-4-(trimethylsilyloxy)pent-2-ynoyl)benzonitrile (0.8 g, 56%) as a pale yellow oil.

Workup

  1. additionwas added dropwise over 10 minutes under an inert atmosphere
  2. stirringstirring
  3. waitwas continued for an additional 3 h at −78° C
  4. customThe reaction mixture was quenched with a saturated NH4Cl solution
  5. extractionextracted with EtOAc (2×50 mL)
  6. washThe combined organic layers were washed with water (20 mL) and brine (20 mL)
  7. dry with materialdried over Na2SO4
  8. filtrationfiltered
  9. concentrationconcentrated in vacuo
  10. customto obtain the crude product
  11. customThe crude material was purified via silica gel column chromatography
  12. washeluting with 5% EtOAc in hexanes

Sources & evidence

ORD record
ord-5d9a3a4a50654999850d8d0d3dcab175
Source dataset
uspto-grants-2011_12
Patent number
US08071595B2

Reaction notes

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