Phenyl 3-methylbut-2-enoate → 2H-1-Benzopyran-2-one, 3,4-dihydro-4,4-dimethyl-

HRID 862260Notes

Reaction equation

HRID 862260 reaction equation
[Cl-].[Al+3].[Cl-].[Cl-].[CH3:5][C:6]([CH3:17])=[CH:7][C:8]([O:10][C:11]1[CH:16]=[CH:15][CH:14]=[CH:13][CH:12]=1)=[O:9]>C(Cl)Cl>[CH3:5][C:6]1([CH3:17])[C:16]2[C:11](=[CH:12][CH:13]=[CH:14][CH:15]=2)[O:10][C:8](=[O:9])[CH2:7]1

Participants

4

Reactant 2

HCID 557821Phenyl 3-methylbut-2-enoate2×HCID 6451240Aluminum(III) Chloride

Product 1

HCID 5953332H-1-Benzopyran-2-one, 3,4-dihydro-4,4-dimethyl-

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a stirred, ice-cooled suspension of 10.4 g (78 mmol) of aluminum chloride in 160 ml of methylene chloride was added slowly under argon a solution of 7 g (39.8 mmol) of phenyl 3,3-dimethylacrylate (Compound 81) in 40 ml of methylene chloride. The cooling bath was removed and the mixture stirred for a further 42 h. The mixture was poured into a mixture of ice and brine and the organic layer separated. The aqueous layer was extracted with methylene chloride and the organic extracts were combined and washed with saturated NaCl solution and then dried (MgSO4). The solvent was removed in vacuo and the residue purified by flash chromatography (silica; 10% ether in hexane) to give the title compound as a colorless oil. PMR (CDCl3 : & 1.30 (6H, s), 2.56 (2H, s), 7.06 (1H, dd, J~8.0 Hz, 1.4 Hz), 7.16 (1H, td, J~8.0 Hz, 1.4 Hz), 7.26 (1H, td, J~8.0 Hz, 1.7 Hz), 7.33 (1H, dd, J~8.0 Hz, 1.7 Hz). MS exact mass, m/e 176.0852 (calcd. for C11H12O2, 176.0837.

Workup

  1. temperatureTo a stirred, ice-cooled
  2. customThe cooling bath was removed
  3. additionThe mixture was poured into a mixture of ice and brine
  4. customthe organic layer separated
  5. extractionThe aqueous layer was extracted with methylene chloride
  6. washwashed with saturated NaCl solution
  7. dry with materialdried (MgSO4)
  8. customThe solvent was removed in vacuo
  9. customthe residue purified by flash chromatography (silica; 10% ether in hexane)

Sources & evidence

ORD record
ord-3730c69b44994e9a9fdf4dd300808022
Source dataset
uspto-grants-1998_02
Patent number
US05717094

Reaction notes

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